Mostly it's about intolerance, a trademark of Salafis. They won't accept any slight difference with what they preach, they can't accept the existance of difference of opinion. That's mainly due to their simple-mindness and ignorance: when someone is very ignorant he will see the world as "black and white". And for them it's their way or no way. But brother, forget about opposing other groups, they can't even stop opposing each othe, amongst multitudes of different Salafi groups and factions. Only in Gaza there are other salafi group other than the one claiming responsability of this vile action. I've read time ago that some years ago only in Egypt have been counted something like 700 Salafi groups (obviously each one of them considering himself "the Saved Sect"... The more I have to deal with them the more I can't stand them. It's true, they may seem "more similar" to us than modernists, innovators and so on, but once you deal with them you'll understand they're pure venom!