It's possible. There's psychological research that suggests people behave in certain ways in groups. There's literally thousands of years of observations about human behavior that supports these notions as well.

> I'd also have doubts with regards to the terms: "many people", "Often" and "especially vulnerable". Is it possible that use of these weasel terms is in itself stereotyping?

Curious. Are you using "stereotyping" in the same category as "sin?" I'm referring to it as a particular cognitive pattern that has certain epistemological problems. People who organize themselves in groups, deliberately set apart in matters of thought and ideology are especially vulnerable to certain forms of group-think. Being emotionally invested in a particular group -- such that you think the inherent justice of its cause makes it exceptional -- is a key symptom.

The evidence against the exceptionalism of a particular group range all of history, and the structure is much the same as certain arguments against religion. Just as there have been so many different "one true" gods and so many different "one true" religions, there have been many, many exceptional "justified" causes. Often as not, they are arguably actually justified in some way as well. Often as not, these causes grow to become the next oppressors. History is full of examples.