When I was a child, I saw "Ace Ventura: Pet Detective" with some of my friends. A lot of people in my generation have fond memories of that film, but for me, watching it for the first time was extremely distressing.
There's one scene in the film in which the main character finds out that he accidentally slept with a trans woman. He declares in disgust that he "slept with a man" and it shows a montage of him trying desperately to clean himself. Later on in the film, he tries to prove to the police that the trans character is actually "a man." He does this by forcibly stripping her until her penis is visible.
At this point in my life, I did not yet realize I was trans. But I understood more or less what I was feeling. So when I saw those scenes, I remember feeling so incredibly ashamed and guilty. The movie presented trans people as inherently disgusting so I thought that must have applied to me as well. I specifically remember watching my friends laugh, as I sat there in silence.
"Ace Ventura" was not the first film to make jokes about trans women. And it certainly wasn't the last either. To this day, we still seem to find the invalidation of trans identities to be funny. For example, just last year, "Ted 2" came out in theaters. The movie featured an incredibly transphobic joke about the main character, John, looking at trans porn. When his friend Ted finds him searching for "chicks with dicks," John declares that he needs "help" and has a "disease." Ted replies that, "There are no chicks with dicks, just guys with tits."
The point of the joke is very clear, that trans women are freaks that are not worthy of being loved or respected. If you are attracted to trans women, there must be something wrong with you.
When I usually bring this up to people, they tell me that humor has to be offensive or it can get stale and plain. But humor can be used to challenge our perceptions of the world while not making punchlines out of marginalized bodies. Humor should always "punch up" (be used to make fun of systems that oppress marginalized people) instead of "punching down" (making fun of marginalized groups). So if you're going to make jokes involving trans people, don't make trans women the punchline, make transphobia the punchline.
People also argue that these are harmless jokes and those offended are just being oversensitive. But it's actually not harmless at all. Humor informs culture, and humor that makes fun of marginalized groups helps reinforce their oppression. Since cis people are taught through media that trans women are disgusting, many cis people end up treating trans women with disgust.
Plus, as a trans person, it can be really hard not to internalize all the negative things you are taught about yourself. Forty-one percent of trans people end up attempting suicide, and making transphobic jokes the norm in media is certainly not helping with that.
Whenever I see a transphobic joke now, I'm brought back to being a kid watching "Ace Ventura." I'm reminded of the shame and guilt I felt, and if I'm being completely honest, still feel sometimes. I also think about trans kids that might be in the same position I was in all those years ago. I wonder if they'll also try and repress their identity for years because of the messages they internalize from the media they consume. And sadly, as long as rampant transphobia continues to be the norm in comedy, I know the answer is almost definitely yes.