Extreme right-wing conservatives seem to feel a need to create things to shield themselves from opposing thought and ideas. Are there examples of the same need among extreme left wing liberals?

Specifically, I’m referring to Conservapedia.
#1.) I don’t understand the reason for shielding your peers from thought, and
#2.) I don’t understand why the moderate conservatives don’t label them ‘fringe’ or worse.

It seems to me that moderate liberals tend to be more confident in their beliefs, more open to discussion, and more willing to label their fringe extreme (albeit somewhat affectionately) “nuts”.

If you’ve read this far (seems few do) my disclaimer is that I was raised by moderate liberals, yet grew into being a moderate conservative. I’ve been dumped in the same boat as both political extremes in my life, but the acceptance of the current conservative extreme embarrasses me greatly, whereas my former fellow liberal extreme amused me.