Honest feedback:
1) "I really didn't like the way you did X. It broke Y on my browser, $Browser."
2) "Oh god, why did you chose to do this like this? It's broken and stupid"
I hope that people don't nerd rage after (1). I guess they might, and if they do that's a problem.
Besides, the worst fights I see among programmers are over trivial matters of opinion anyway. Ever seen people fight over indentation styles, or the proper way to merge upstream changes into a local git repository, or whether functional or object-oriented programming is the One True Way?
The anger in these debates isn't teaching anyone a damn thing, except that the color of someone else's bike shed is really, really important to some people.