I actually have blocked some. If you can send me the full blocked IP I'll check it against my block list.
And yes, I've have intentionally blocked some entire ranges because the preponderance (and to my knowledge at the the time - all) of the requests came from Europe, Asia and Africa.
I've had some members who traveled to Europe email me (emails are typically not blocked) to complain.
Frankly, this was done because there are always places on a forum as large as pcom that can be accessed and posts made. (I've had some minor forums that were set up specifically for anonymous postings at time and guests could post and sometimes even reply and validating members can/or could/ access the PM system.)
When porn, spam and links to content with viral alerts result from a range that appears to come from say Russia, I don't care - I'll nix the whole thing.