Not from any universal morality, but out of common sense. You go through life, trying not to piss people off... and if you do, you expect consequences. Otherwise you are a fool. Perhaps a brave fool, but a fool.
It's certainly not a good time to be rude, but it's always a good time to state the obvious.
Re: "They weren't trying to piss people off."
It amazes me that people don't realise that their intentions are never perceived as they intend :D
Of course, every action havings its appropriate reaction, we should also expect this: http://www.telegraph.co.uk/news/worldnews/europe/france/11335676/Hacktivists-Anonymous-says-it-will-avenge-Charlie-Hebdo-attacks-by-shutting-down-jihadist-websites.html
And so the world turns.
I'm not advocating anything. I'm stating the law of nature. The rest, is merely our cultural preference ^_^
