<img src="http://www.geofferic.org/mattpegs/pics/lcg.jpg">
Tony has thrown a hissy fit/temper tantrum in the past, and the reason for it never really matters that much to the others. they never really talked about taking him out based on the fact that he threw a brutal temper tantrum. i think a lot of the hierarchy really is based on strength and show of force.
however, weakness is never tolerated (look at how they turned against sack just because he cried at the wedding). it's more important to show physical, macho strength than it is to have a reason to show it. tony had to do something because they were calling him an invalid and the whole bodyguard thing just symbolized everything he lacked. showing that he had the force of will to take down a guy that strong just showed that he never even needed the bodyguard to begin with. in less than a minute he completely put all of that shit to rest for good, and it was really the only way he could do it, and he knew it.
i think the others knew that he was "wrong" to knock that guy down but they also understood why he needed to do it. and i think he knew that they knew this. actions speak louder than words.