It's more about the fact that with drag, it's extremely difficult to draw a line. It's not that drag is supposed to offend, it's just that it's in its nature to offend at least some group somewhere.

People without vaginas making jokes about having vaginas is always going to be problematic to some people. Some will see the humor, others will find it sexist. But if a majority of people can agree that it's not meant to be offensive and it's all about being playful, can't that apply to other types of jokes?

At some point, it's easier to adopt the mentality that "nobody's safe from humor" than to try and categorize a bunch of extremely subjective matters. Everyone is offended by something and indifferent to something else. You can try to rank "levels" of offensiveness, but someone will inevitably disagree with you because they find something else a lot worse.

It's not productive to focus on that instead of just looking at it for what it truly is: playful jokes that have no malice at all behind it. The line should be drawn at something hateful. Saying Acid Betty played a "schizo" well is not mean spirited. Tyra Sanchez saying "Kill yourself, suicidal people are cowards and I'm never going to feel bad for them", that's mean spirited.