I could be wrong, but I am almost positive that this is what was being argued.
Rogan himself was holding back from joining in, and I think some of the commenters here mistook my comment as critiquing Rogan for being transphobic, which I did not observe. It was the skinny guy (whose name I don't know).
I think the purported advantage of puberty blockers is that they help “waiting a few years so you’re sure” while taking the path that’s the lesser of evils.
You can't be that surprised that in a situation like this, most people would tend to be very conservative (not republican conservative, but careful, do no harm, don't rock the boat kind of conservative).
Most people are "conservative" on this issue because they have no idea what they're talking about, just like every almost every other issue related to trans people.
My mom said something similar about "curiosity" to try and convince me that I couldn't be trans. As it turns out, what she meant was "when I was your age, I wanted to cut my hair short." Likewise, pretty much every story I've heard like this turns out to be either obvious lies meant to discredit trans people, or something that would have been easily sorted out by a psychologist. Eg. I've heard of gay people wishing they were another gender so that they wouldn't get bullied for their orientation. No decent professional would mistake that for genuine dysphoria.
But even supposing that your psychologist was incompetent, you still would have socially transitioned in some capacity before you ever started hormones. This almost certainly would have let you know if transitioning was really right for you. And even if it didn't, and you went all the way to starting estrogen, you could always stop if you didn't like what it was doing. Estrogen works very slowly. I've been on it for three years, and I know cis men whose boobs are bigger than mine. If I changed my mind, I could easily start living as a man again.
It's absolutely unfair to impose life-ruining misery on trans teens because of the off-chance that it might do a fraction of the same harm to a cis person.
Case in point: Rogan talks a lot about fighting. But in that particular case, we already discriminate by weight. So it might be possible to make things more fair by giving a weight penalty to male-to-female fighters that want to compete in the women's league.
My point is, there are options to explore besides an outright ban. For example, a trans woman that goes through HRT will lose some of the advantages of her birth sex. However, she might still enjoy the advantage of the male frame, hence my suggestion of an additional penalty.
A unisex league as you suggested could also be a posibility, and one could think about introducing not only weight classes, but testosterone classes as well.
The reality is that female leagues was a cultural hack that worked well enough in the 20th century. But in a world where we recognise that neither sex not gender fit neatly into binary categories, it is impractical to assume that we can fit people into two sporting categories.
Before the higher level of testing, there were plenty of rumors that fighters would overtrain (or cycle on steroids) to the point of plummeting their testosterone levels to be given a TRT exemption. By the time their baseline levels recovered by fight day, they could still be on TRT
Trans women are rare, and transition dramatically reduces muscle mass and other attributes related to performance. In fact, trans women typically have a lower testosterone level than cis women due to hormone treatments. There's absolutely no reason to believe that allowing trans women to participate in sports would prevent cis women from being able to compete. Trans women have been allowed to participate in women's Olympics events since the early 2000s, and not a single one has won a gold medal. You use the term "biological males" to refer to two completely different sets of people, which is dishonest and despicable.