Can't an omnivore eat at a specialty restaurant?
I must have read your incredible message at least five times.
The part about sticks and holes read like a math problem. I'm still thinking about it. I feel like I'm trying to solve an unsolvable riddle: "Now, assuming Takashi-kun is a switch, how many times at most will he be used as a hole?"
So, the gist of your consultation appears to be that you're an omnivore, but you want to get along with those fixed pairing enthusiasts and be a part of their community, right?
If you just want to read the works of fixed-pairing fans despite being an omnivore, the answer is to read them in secret.
You don't need to sign away your soul and swear to only love male-female pairings (hashtag femdom/no role reversal) to view content on pixiv. That'd be like saying people who enjoy the Brazilian martial art of Vale Tudo aren't allowed to enjoy even reading a manga about karate. Ridiculous, right?
Openly expressing your appreciation for their works after reading them may reveal your omnivore identity, causing you to face salty omnivore-shaming or get blocked (the horror!), but if you enjoy your meal quietly and leave without leaving a trace, however, that's a different story.
I guess it's possible that you're well-known for having such a big appetite that you often eat the whole restaurant out of house and home, to the point that people have given you a dramatic moniker like The Devourer and speak of you in furtive whispers. If the moment you set foot in a joint, alarms start blaring and a "Closed" sign is hung up, you might need to really look hard at yourself and your behavior in fandom, but that is unlikely to be the case.
Sure, going about your meal quietly has its limits since there are posts with restrictive privacy settings.
Back in the ancient days of personal websites, we had password-protected content too, so not much has changed in that regard. To get the password, you had to send a message to the admin and tell them how much you love that particular pairing and how badly you want to see their racy illustrations.
Sometimes you'd send a follow request and they'd look at your profile and say, "Sorry, no omnivores here," or that they only accept requests from fans of fixed pairings.
However, I'm getting a sense that you, an omnivore, are saying that you want to sample not only the dishes on the menu but also the secret menu that is only available to the most discerning customers of renowned specialty restaurants. Certainly, it doesn't feel fair to be rejected and have an old packet of mystery seasoning thrown at you as they sneer down at you and snidely say, "You'll eat anything, right? Then you should be happy to just eat this!"
However, the reason omnivores may perceive a fixed-pair enthusiast as an unfairly mean and unwelcoming specialty restaurant owner is that they themselves have few or no potential triggers and thus have an underdeveloped understanding of those who do.
Seeing other people successful makes me sick
Triggers are like allergies, which is a little different from just being picky. For fans of fixed pairings, being exposed to reverse pairings is more than just an annoyance; it can have a profoundly negative impact on their emotional and physical well-being.
By the way, the success of others is my trigger. Just seeing news on Twitter in the morning about someone's work being adapted into an anime or selling a million copies is enough to depress me for the rest of the day. Sometimes it's so bad that when I wake up the next day, I think to myself, "Oh yeah, that was made into an anime," and my mood drops again.
It's not that I hate the work itself. Most of the time I don't even know the author personally. But just being in the same room as other people's success makes me feel sick to my stomach.
People who don't have triggers won't understand the feeling; when they hear that I mute hashtags like #animeadaptation or #reprint, and even specific work or author names, they probably think I'm going too far and being too sensitive. Sometimes these kind and well-meaning people like to tell me that it's pathetic and narrow-minded of me to be this way, which inevitably makes me feel even worse about myself.
In other words, people with triggers have to deal not only with the initial bad feelings that are caused by triggers, but also with the self-loathing that can come from feeling that way and the isolating feeling of receiving a lack of understanding from those around them.
The owner might be wearing a gas mask and a full-body protective suit
Those people are very careful about how they live, making sure they don't touch any triggers by accident and hurt themselves. They mute every possible trigger word and try not to see reverse pairings in tweets, retweets, or likes. They will even refuse to follow back people who enjoy reverse pairings or omnivores who are open to different pairings in general.
Despite that, Twitter's mysterious algorithms will sometimes show them their dreaded reverse pairings under the heading "Recommended for You". There's really no winning, but they still have to try!
Imagine walking into an udon restaurant right after having soba, only to have the next customer's hands swell up three times after touching the faucet you twisted to wash your soba-brothy hands. That's (analogically) what you're doing to the people who simply cannot deal with anything other than their fixed pairing, even for a brief moment.
The unwelcoming shop owner you see dressed in a black T-bandana with his arms crossed menacingly across his chest is actually doing the equivalent of wearing a gas mask and a full-body protective suit. If they take it off, they might die, seeing as the soba noodle aroma wafting from your mouth may have already left polka dots all over their body.
If the restaurant owner is being extremely adamant about keeping you out, it could be because they had a terrifying or even near-death experience there once and they're trying to avoid it happening again.
Focus on the freedom, not the inconvenience
We are all born with our own set of inconveniences and difficulties in life.
People with strong triggers have to deal with the fact that they don't know when they might (analogically) step on a landmine and die in the explosion. People who try to protect themselves by limiting who can see their profiles or by writing long disclaimers are often criticized for wanting to keep their posts to themselves and/or are accused of being annoying fixed-pairings extremists.
But that doesn't mean that omnivores with no triggers whatsoever live carefree lives with no problems. They also have to deal with the challenges that come with being omnivores, like being unable to eat at certain places because of it, being accused of lacking sensitivity, or being blamed for wanting to try limited-edition foods even though they already have so much to eat.
Only you can truly understand the inconvenience and hardship you're experiencing. As someone with no triggers, you can't really understand the pain of being a pure God's Child dropped into this minefield of corruption. You might be standing in front of a locked gate where a Doberman won't stop barking at you and think, "Why go to such lengths? I'm not looking to make trouble."
Even if you don't fully understand the situation, it's worth it to extend some empathy. Sure, you've got a scary Doberman ready to rip your throat out right over there, but the person behind the big dog probably has their reasons for going out of their way to make their bite worse than their bark. Then, since you've got the freedom to, make your merry way to that creative restaurant over there that has generously(?) added ten original characters to the source material. This is a way to be considerate of others while embracing the freedom that comes with being an omnivore, rather than getting hung up on the inconveniences.