Here's a hint...the comedy ones aren't doing drag time story hour....there's no point....you can't do your character and you can't get the laughs if you are reading a story.....the ones doing it are seeking to share what they consider high art with the kids, and thereby get them to appreciate it. The objection is no, that's not appropriate, because that particular piece of art has a sexual component to it which is not appropriate around kids, anymore than stripper time story hour would be, or for that matter taking a young boy to Hooters.
It's not just story hour either. Objections have come from people to parents bringing their kids to drag shows and stripper shows that are toned down for kids (no nudity, no simulated sex) but still have a sexual component (like pole dancing) to them. The defense of them is "it's art".