Lots to unpack, urko. First off, let me apologize for any offence caused. I've been touchy about specific use of language on the board in the past, so it would be hypocritical of me not to accept that my use of language may have offended someone.
As regards whether something is offensive dependent on the audience, I think that's a false flag. One of my students, many moons ago, made reference to the concept of women belonging in the kitchen and, when I pointed out that his reference was sexist he responded with "but there aren't any women here". You don't need women to be in the room for sexism to be sexism, of course.
You said you couldn't see the irony - but I made a joke about trans genitalia on a thread about being woke, in response to a man making jokes about trans people and being defended by a trans person. Surely this has some irony?
Stewart Lee adopts a persona on stage, but still calls himself Stewart Lee. In interviews, he often refers to the fact that the stage persona is not entirely him, but rather an exaggerated version of him - a version that has adopted a superior intellect and looks down on his audience. He often splits the room into sections that "get it" and sections that don't, which allows his stage persona to get frustrated when sections of the audience don't understand his carefully crafted humorous scenarios (despite the fact that he's created the illusionary division).
I mention this because Funt Solo will sail far closer to the wind and be more outspoken and risque than if I were to meet you all in a pub or at a con. Funt's a cheeky bastard. I'm more introverted in person, very careful about exposing my political views in the workplace (because I have a duty of care, and a professional interest in allowing students to manage their own narrative directions*) and only really open up with people I know very well.
As to the context of my joke, it all started with milstar posting an article in which Caitlyn Jenner defends Dave Chappelle's right to free speech. Dave Chappelle had done a routine in which he was apparently openly transphobic (although I haven't seen the routine, so I'm not sure what he said), and complaints were made. Caitlyn (in the article) says he has every right to say what he said. Whatever you think of the article, or Chappelle, or Jenner - one thing is clear - there's no point in engaging in a debate with milstar**. So, that option is out.
Next, Jim responds to milstar's post with "complete bollocks", but milstar wants to know if he means he doesn't believe the article is real or if he means that Jenner's opinion is shite. Jim (I assume) realizes there's no point in engaging in a debate with milstar, so doesn't respond. I don't try to elicit more information from Jim, because sometimes he gets touchy when I do that (sorry, Jim).
So, my motive at that point is to try and derail milstar's prodding by making a joke that both Chappelle and Jenner would approve of, about Jenner's genitalia, but which I personally find mildly offensive. The joke, not Jenner's genitalia, which (frankly) is none of my business, and I know nothing about - my ignorance of actual fact also being part of the humor. Aware that this is all skating close to the edge of polite frisson, I add the *Too soon?* as a signal that I'm aware of where I'm skating.
The other part that's worth mentioning here is that society is, of course, obsessed with genitals. Our own, other peoples - what could happen if we get hold of them and so on. You could say it's built into us. When people transition, then I'm sure they have some thought about their physicality and of course other people have a natural curiosity. Now, if a trans person is being interviewed about their new, say, movie - it's not really acceptable that the interviewer would focus on their genitals (unless it was a movie about their genitals), because when actors are being interviewed about their new movie, it's a bit pervy to start going on about their personal business. There are great videos online of Tom Hardy and Scarlet Johansson ripping interviewers a new one (more undercarriages!) for getting too personal.
Of course, in a personal relationship, whether you like bearded or non-bearded people, or bald or non-bald people, or particular kinds of junk, is entirely a matter of personal preference, and perhaps part of your lifelong family planning, but it's not otherwise anyone's business what you're carrying around in your undergarments - which is why it's such a stupid thing to focus on, but one that people nevertheless get obsessed by. Ripe location for a joke.
You did ask if I would tell the joke in front of a trans person. I don't know, is the only answer I've got. I think it would depend how well I knew them. It was a very contextual joke, and it was Funt that told it. I'm finding it difficult to extrapolate that out to a different scenario. I was driving two folk along one day, and one of them said "that building is so black" (in reference to a particularly black building near Edinburgh) and the other one said "racist!" Three white people in a car. Food for thought.
And, again, sorry for any offence. And the accidental fish pun.
*Unless they're being openly racist, sexist, homophobic or transphobic (or otherwise bullying someone) - because I run an inclusionary classroom.
**Due to a historic tendency to eschew evidence contrary to his original position.