Kind of sort of, but at the same time they were also former soldiers, who thought they'd been forced to surrender when they still had a chance of winning, who organized themselves into a political party.
Any group that sets itself apart and has a burning collective desire to change things is waking the same psychological mechanisms. So is cheering for sports teams. We're a bit more savvy as a culture about harnessing and controlling that in the case of sports. Yet, look at some of the stupid stuff ports fans still can get up to. Just look at history, and it's quite apparent that politics awakens the exact same tendencies, but without the same cultural/societal checks. Hell, just listen to what people say and observe how they start to prejudge and target each other based on surface-level signals.
There are certainly collective behaviour instincts that can kick in with groups and which can be manipulated to cause people to run amok, but it's not any group by any means.
Take for example the English Society of Friends (Quakers), and their burning collective desire to stop the Slave Trade. (& for prison reform, but that was arguably self-interest because they kept ending up in them.)
So perhaps the more interesting question is still which groups and why.
