I think half a dozen, and one of them on this thread.
It hasn’t been a mystery for any of them, though in one case the blocking seemed to me a massively disproportionate reaction to the offence. But that gets to be their call to make, not mine.
I’ve been blocked and unblocked once on the matters *I* regard as my core domain, the union of Greek and Language. Most of the blocks relate to the matters everyone else likely assumes are my core domain: assuming the mantle of being a Quora critic.
In my estimation, I’ve gained more from those I’ve come to associate through assuming that mantle than I’ve lost.
And that gets to be my call to make.