I was raised in a conservative Christian family that belonged to a church denomination branching off of Mormonism - It took (is taking?) years to deconstruct and understand the hate that I participated in and supported.

I strongly recommend watching the movie Jesus Camp to get a better understanding how Christian youth groups/camps can brainwash kids so they grow up to become adults who are so ignorant of the world outside their small Christian community that they know little more than what church authorities tell them. In my case I hated the LGBTQ+ community because hating you was my identity. I was taught to be one of "god's chosen people" preserving the correct way to live. It was often preached that natural disasters were god's way of punishing non-believers and those whose faith was not strong enough. The congregation I attended literally believed that all the natural disasters, pollution, and systemic failings around the world were god's vengeance against gays, liberals, and socialists. - e.g. I attended a sermon where the 2010 BP Deepwater Horizon oil spill was literally and explicitly blamed on Obama's support for gay marriage.

If you were raised in such an insular, dependent, and ignorant community it is most likely you would learn the hate too. When you believe you and your religion are literally the center of the universe (you are the "chosen people" in a supernatural power struggle between good and evil) you too would feel anxious, threatened, pressured and quick to resort to violence.

The conservative Christians I grew up around who hated the LGTBQ+ community were generally emotionally immature. Their personal development, like mine, stunted by the church from an early age. It takes years to unlearn the judgemental conformity, moral superiority, and cognitive dissonance that is so integral to many congregations and denominations today. Faced with the prospect of questioning your core-beliefs, leaving your friends and family behind, and abandoning so much of your identity it's totally understandable, yet horrible, that people will choose to double down on the only beliefs they really understand.

That's why I hated the LGBTQ+ community - Because I was taught that you were the root of so much supernatural evil in the world, but if I were asked "why do you hate gay people" I would have told you "I don't hate gay people, I hate their actions. I just don't like them, it's unnatural". Eventually I realized that people are their actions and you can't hate one without hating the other.