Unless your device is forced to have a rainbow wallpaper, it’s not being forced upon you. Your annoyance that it’s an option does kinda come off as aggressive in a “I don’t care what LGBTQ+ People do in their own homes and bedrooms, but i don’t want to see it!” That’s why people got defensive. No one is forcing anything on you, and the rainbow is part of Apple’s original logo design in addition to being a symbol for the LGBTQ+ community. Do you want them to get rid of the Apple logo on startup too, or are you maybe unnecessarily annoyed by an optional wallpaper?
As far as the App Library showing apps you have installed, that’s its function. They aren’t folders because of the algorithmic nature of them. Maybe a way to customise this feature would be to, in the same space where you can choose apps to be ignored by Search and Siri Suggestions to have a toggle to not be favoured by the algorithm in the App Library category pages. That way people could deprioritise apps they want to keep private or already have on the Home Screen (including if there’s a widget on the Home Screen). That could be a cool implementation. And, speaking of LGBTQ+ people, it could help make closeted people safer with such a privacy option.