I judge silently. I normally don't care if some "elderly guy" () is grabbing his rear brake or eating mud. I do however cringe and look away when I see somebody not paying attn. and bashing a derailleur on a miss'able rock or bash the crap outta the rear wheel smacking into crap.

I suffer silently though. I'm not the type of preck that comments on a stranger's riding style. That's just tacky.