Explanation (from a neutral third party standpoint)
People likely would've interpreted you saying "i don't believe in LGBTQ stuff) as being homophobic, just as some people saying "i don't believe in God" to be anti-christian
It seems likely the comment got flagged multiple times, and whoever the moderator was decided that it would be better for the majority if the comment was deleted
That's just a possible explanation, not necessarily the exact reason