Now, I agree with you: the vast majority of that kind of assholish crap isn’t *really* threatening. Most email or comment threats are just hot air. But at some point, some dickhead is going to stir up enough craziness that someone really *is* going to get attacked in real life as the result of some online bullshit.
Codes of conduct aren’t going to prevent that, of course. Maybe nothing will. But people like you and me *can*, I think, postpone its happening, maybe even make it less likely, by not just saying (in effect) "butch up or quit blogging." The voices of vulnerable people matter too. Maybe even more than the voices of those of us who aren’t easily intimidated.
…those of us who provide readers with opportunities to respond–in blog comments, or on online forums, or in chat groups–need to make sure we come down hard on assholes who use those opportunities to hassle, harass, or threaten people (including us). For god’s sake, don’t make excuses for them by pretending that they’re some kind of force of nature, like an earthquake, that we can’t do anything about. Because we can, if we shut them down when they show up.