I think this is actually quite a working class trait as well, calling a spade a spade.
Whether due to their level of education or, if well-educated, still being in touch with ordinary people, I feel that working class people are less afraid to make simple statements such as "women don't have penises".
They know that the people around them by and large agree that women don't have penises and won't think any less of them for saying it, and they don't much care for the opinions of people who can't explain why they think some women have penises without descending into incomprehensible waffle.
When you look at middle class people - and I realise that the middle class is so big as to be almost a meaningless term these days, but let's say university educated people working in professions - there's a lot more insecurity there. They like to think of themselves as being above working class people when in reality they might not be any financially better off, especially these days. They attach an awful lot of social capital to things like having a university degree and a fancy job title and for them it's much harder to say, "I don't understand what the hell you are talking about."
I think there's a part of them thinking, "There are some very well educated academics and politicians and people in positions of authority saying women can have penises and even though I'm a bit hazy on how all this gender stuff works I'm sure it's true, and trans people are after all the most marginalised so I can afford to be magnanimous, and overall I'd better just take their word for the fact that some women have penises. After all, it doesn't really matter, does it? We're all people."
It's a combination of their own insecurity in not wanting to be the one who stands up and admits that they don't have a clue what any of this gender stuff means, and the security of knowing that they'll almost certainly never end up in prison or in a women's refuge so they don't give any thought to the consequences of all this for women who are in those places.
Unwillingness to admit when you don't understand and relative privilege shielding you from the consequences of your lack of understanding are a disastrous combination.