I'm going to go out on a limb here and say that almost no one is watching this movie and is actually "disgusted" by an on-screen same-sex kiss. It's more about where people, especially parents, are comfortable drawing the line for how much exposure to LGBT content is okay for children. Just about everyone is happy to have same-sex relationships represented in media and to raise their children to tolerant and accepting of other people's differences. The issue is that relationship diversity is almost universally hamfisted into every form of media to the point of it feeling inauthentic (and not really reflective of the community) while simultaneously over-representing minority groups. I can see where some parents believe awareness transitions into propaganda.
Me personally? Despite being right-leaning, I believe that same-sex relationships can be explained just as easily to children as heteronormative ones, and whatever was shown in this movie is a big nothingburger. As long as everything is held to the same standards, of course. I don't want to be called a bigot in 10 years for not supporting a gay anal sex scene in a Pixar movie.
