The speculation of others has made it impossible to enjoy the original work
No matter how good the theories are, the original work is the only canon.
Unfortunately, I didn't win the otaku lottery, but I'm still one at heart and I like to learn more about works and characters. That's why I'm grateful to the people who won that lottery and are kind enough to share their deep thoughts on the Internet for free.
When you say that the development you all witnessed was a bolt from the blue, it may sound like you're all just a bunch of angry otaku, disappointed for not being able to live on their delusions.
But there are only a few people who go as far as to completely ignore the original story, making up fantasies like having totally seen those two characters make out between panels.
There are way more people, however, who read deep into the original story and create their own theories based on their observations: the panels are 5mm wider apart than usual, which means the characters are kissing in between.
If the story takes a turn that ignores all the hints that they have gathered so far and if there is no follow-up to their theories, these avid readers may be taken aback, and the author's inability to make things square is often deemed as a lack of skill.
However, speculations and fan work are things that wouldn't exist without the original work and the canon created by the author.
It goes without saying that there is no such thing as fan work that is more canon than the original, no matter how good your theories are or if you use tags such as #looks official.
No matter how disappointingly the original story unfolds, that is the real thing, and no matter how good the speculations and fan work are, the real thing can't be beaten. It's the burden of those who have made it their hobby to play with what others have created; if you don't like it, you'll have to start creating your own original stories.
You're bothered because you're looking at things through someone else's eyes.
However, the only good reason you may want to look into other people's thoughts is to broaden your own perspective.