To me, when it uses the exact same rhetoric as the people who take it seriously, it's not really a joke. Or at least it's not a funny joke.
"Haha, bisexuality contradicts non-binary identity," isn't really funny to me because a) it's not true, and b) I've seen cisgender bisexual people seriously put forth this notion in an effort to reduce support for transgender people. The "drop the T" movement has used almost your exact same language to try to illustrate through humour that trans people don't belong.
I'll admit I'm sensitive, but these phrases aren't really jokes. It's basic (and lame) wordplay at best. It's inherently stale, like the "I identify as an attack helicopter" and "don't assume my gender" crap.