Ok, go for it

Denying the reality that there are some people who aren't XX/XY or have differently formed parts is transphobic, absolutely. 

How are we supposed to be familiar with these comedians? Surely they've been locked up by allegedly liberal policies. 

Most trans people are indeed XX or XY and don't have differently formed parts before they transition/operate.

You are mixing up completely different things.

Because of course you don't. But that wasn't the point of my post, now, was it?

I think if someone is insisting that everyone in the world fits into these two boxes to justify their transphobia, while ignoring that biologically plenty of people don't fit into those two boxes, that's a meaningful discredit to the idea. 

I don't know. Sure there are people not fitting into the XX/XY boxes, but these are not trans people, that are people with chromosomal abnormalities like Down syndrom. Mixing that up with trans people is highly problematic I think.

I also think it is wrong to justify trans people by claiming deviations from the biological binary. Because in nature that are rare outliers. They exist, but that does not disproves the binary of biological sex.

Trans people are different anyway, their sex is completely clear (usually), but their gender which is influenced by a lot more than just their sex is differing from that sex. This can (but not always does) create distress, something which is called gender dysphoria. Conditions like these are often dismissed as not being physical, but the reality is that given the prevalence for suicide it can cause death, and even besides suicide it can cause major pain in the person. Modern medicine may be able to alleviate this pain. This may include hormone therapy and surgery for transitioning, although other options exists. As gender dysphoria is a real and painful thing any health system that is worth the name should cover that.

And trans persons without gender dysphoria also are humans and be treated as such. Decent people can be accepting of that.

See: I can explain trans people and the medical help they may need without resorting to claims of broken sexual binaries, which are on shaky ground to begin with and also not really related to trans people, as most trans people have a clearly defined sex.

Also, to get back to the topic: every person and group in the world can be made fun of. If done with proper respect this can be very inclusionary (as claiming some groups are disallowed to be made fun of can feel patronizing and exclusionary). If done with disrespect it is a bad taste joke - which exist for millenia and usually are treated by ignoring them.

Oversimplifying an issue in order to justify bigotry while presenting it as comedy is absolutely omega behaviour.

All comedy is an oversimplification, if you would explain the world in it's complexities it wouldn't be funny. Instead you draw an essence, a simplification, to make fun of that.

In a sense, sure, but that still doesn't mean that it can or should be used as an excuse for bigotry. It's fine to oversimplify something for the sake of comedy when you're not 'punching down' on marginalized groups. There's a world of difference between the two.

Eh, punching down is also a complicated matter. But sure, there are unfair jokes or jokes in bad taste.

But a lot of the examples named here are actually "controversial" because they attack religion. And religion did so much damage to the world. So I enjoy a good religion roast, like Carlin (who was mentioned in this thread) does:

https://www.youtube.com/watch?v=_BFIRgn9OLI