You are talking about religion. Which is far a different matter. Unless you're trying to say that transgenderism is a religion. Which I don't think you really are. But the comparables are there.
People who can't answer the question either don't because they know the truth will offend people and they don't want the backlash from it. Or they don't believe in a truth.
I've heard the interviews. "Who's truth are you talking about? Your truth or their truth?"
It's an ideology. A belief system that is not based upon anything real.
Actually, I don't see them as being terribly different in that regard.
The belief that a man can become a woman and vice versa is just that...a belief
...much like a belief in things like the concepts of Karma/reincarnation, which is also a belief system that's not based on anything tangible.
Yet, we don't see certain people feeling the need to regularly grill Hindus on the hotseat about their belief in that.
Asking them to define woman isn't in good faith?
In the context they're doing it, it's not most of the time. It's meant to give them the choice of "looking silly and having their comments re-ran 24/7 on the partisan news for the next 3 days, or having their own side think they're not actually on their side"
If you (as a Christian) were running for some sort of office or looking to get confirmed by some legislative body. (these are hypothetical, not sure what your actual positions are)
And I very publicly asked you these types of questions (in the same tone that Ted Cruz often uses when he grills people, sometimes for good, sometimes disingenuous):
"Can snakes talk? It's a simple yes or no question Mr. Rjs"
...or...
"Mr. Rjs, you've said in the past when discussing abortion that if people don't want an unplanned pregnancy, they should just avoid having sex until they're ready for the responsibility, is that correct? Your belief is one that's heavily rooted in the belief that a virgin got pregnant, is that also correct?... so then I have to ask, how do you see abstinence as a solution for this if virgins can get pregnant? ...or is it impossible for a virgin to get pregnant?"
That would be a bad-faith discussion, very different than if you and I were at a restaurant having a much more private conversation and the questions were rooted more in legitimate curiosity.