Peer pressure can make smart people do dumb things. And since Crossfit has peer pressure and competition built into its very core, the rates of injuries and potentially-fatal medical conditions like rhabdo are a lot higher.
As for peer pressure - I think when a person above 22 or so of age is not able to withstand peer pressure to do something he thinks is harmful for him/her, there's something wrong happened on the way. Adults are supposed to be able to say no. Of course, you may make a choice to push yourself and take a risk, but that's what being responsible adult is all about - seeing where are the bounds of acceptable risk (and those can be different from person to person) are for you. Of course, again, good teacher is important - so you could always can consult what would be good for you on this exercise. Good coach can see how you do the exercise and tell if this weight or this form is good for you or you have to scale it down. That's where you have to, again, master your ego and be responsible too.
And of course it is a given that you shouldn't go to a group which has different views on how competitive it should be and pressures you into something you're not ready for. There's a lot of difference between supporting and cheering somebody when one chooses to push oneself and pressuring somebody into doing something one is not ready for. If you find yourself in a group that does the latter and not the former - just leave. There are a lot of better settings.