"Fuck all" is just a slightly course way of saying "nothing." It's not an insult directed at a person. pg himself has used the word "fuck" on this board [1], so I assume it's not necessarily proscribed. We're all adults here - at least I proceed on that assumption.

[1] http://news.ycombinator.com/item?id=1766387

I myself use profanity from time to time in in-person discussions with people I know, so this may seem a bit hypocritical.

The reason I try not to do it online though (or in person with strangers) is because I have marked that when you use profanity with strangers (especially online) it tends to make the discussion more rancorous because people focus on the profanity instead of the content. It does not seem to matter whether it was meant as an insult, or simply as an "emotional multiplier".

I have certainly realized that I used do it, so may be it's just a bad data point, weighted heavily!

So that's my perspective.