I’m not saying that I don’t accept LGBTQ, this is just what I have observed. Some people just believe same sex marriage/relationships are the normal, and LGBTQ is strange or something that isn’t a normal ritual in society. (Particularly the elderly/older people, that grew up with this particular feeling towards them) Their parents may also have these opinions, which can influence their children to believe them because they look up to them. This can lead to a chain reaction.
It might also be because of their religion, and they aren’t accepting of them because they think god doesn’t accept LGBTQ