I know we shouldn't assume BUT I have always thought you were an adult male? If so, why would you watch a movie that was primarily made/targeted for preteen/teenage girls?

First of all I like animation and Pixar was doing great movies before, that were interesting to watch for adults as well. And second, there are multiple situations in which you can find yourself watching such movie. Like when you take your kids to watch it. And the fact this movie is mainly targeting preteen girls is already a reason for valid criticism.