LGBTQ+ treats incest no differently than how everyone else treats it. It's still generally taboo, and since it's not a sexual minority suffering from unjust persecution/discrimination, it is not offered any special protections.
Incest is condemned largely because it often takes the form of rape due to power imbalances.
No, nobody likes incest porn and most want to ban it, which is why it’s a smart strategy as a person who wants to censor things most people don’t find disagreeable to take actions against incest porn which conveniently just so happen to also affect lgbt stuff.