This is a very good point. I worked with a group (when we were a very small team at a startup) where we would say terrible things about each others code/ideas m

This is a very good point. I worked with a group (when we were a very small team at a startup) where we would say terrible things about each others code/ideas more or less for fun, as we had a long-running relationship and understood that everyone respected everyone else. Once we were in a bigger company, we had to stop talking like that (at least in venues where others could hear us) as the perception that we were "ripping each other apart" could be perceived as very threatening to people who didn't have that rapport nor the understanding of the background. The perception would be that we were mean people who might turn on them at any moment. The argument that "oh, X can both dish it out and take it (with respect to criticism from Y)" often ignores the fact that somewhere, "Z" is quietly watching this interaction and deciding that they don't want to participate in this apparently hostile environment.