One thing that's interesting to me, not necessarily related to anyone in this thread:
Some people persistently make the same basic, simple mistakes over and over (its/it's, your/you're, their/there/they're, apostrophes where there should be none, etc.), and also hate "grammar Nazis." As if the fault is with the people making the criticism and not the person making the error. Why is that? I would understand if someone couldn't spell esoteric words or something, but I find it hard to have sympathy when someone consistently makes mistakes that should have ended in middle school and then lashes out when people try to correct him.
Ostensibly, the reason people lash out against "grammar Nazis" is that the criticism of grammar errors is a distraction from the argument. But then, isn't the person lashing out doing the same thing? A criticism of grammar may seem petty and tedious but it pertains to the comprehensibility and credibility of the post. Criticizing someone for being critical of grammar errors almost seems like an ad hominem.