Out of curiosity, I have navigated to look for a blocking option. I see none. Are we subject to everyone, unequivocally...all of the time?
There is no option to block another poster. You can put someone who sends you a PM on 'Ignore' but that just prevents them from sending you another message. If you are having issues with another poster then you should notify a Moderator via PM or by filing an "Inappropriate Content' report on one of their posts.