There was a comment that summed it up rather nicely but can’t remember where it was. The gist was that conservatives view anything other than heterosexuality as deviant and associate sexuality with sexual fornication.

They don’t understand or even comprehend that they aren’t the same thing. So for them, simply saying the word lesbian is pornography because they can’t see it as two women in a relationship like they can with heterosexual relationships.

Also, the whole “out groups” and “in groups” thing.