No clue either, but interestingly the reader mode was available after I disabled content blockers (that's on Safari on Mac). So I take it back; I read the post and it is quite interesting :)
I am curious now, how did you come to get interested in this topic?
That font, though... It's not that it sucks in general, but it is a bit too quirky to be read comfortably for more than one sentence. At least to me. The combination of sharp angles, irregular curves, and seemingly randomly varying thickness.
Otherwise I haven't disabled the reader view, I don't even know how this is done.