I don't view it as blocking people out. I view it as a way to not allow my presumptions about other people to influence how I talk to them, or don't.
I have no trouble with such things, so that doesn't bother me.
All I know about people are what they post and have posted - this tells me who they are
on the internet.
For example, Regulith is a lovable nutcase who enjoys explaining his various thoughts via reddit-emoticons! Using this information, post accordingly.