I think the students' behavior is disgusting. But I'm pretty sure this incident would be little more than an "interesting footnote" if it weren't for the media coverage. Students acting like assholes is not a new phenomenon. It's been happening at colleges for hundreds of years What is REALLY changing about society is that our perceptions are shaped by social and online media whose single objective is to drive traffic. That should worry you more than Evergreen and it's students.
Collegiate administrations have a tendency to only react to that which may imperil the fundraising, so we'll have to see how that aspect plays out. But for the kind of person involved in this sort of fracas, "tone policing" is just another example of "privilege" and will only get further adverse reaction.
But that's what happens when everything is looked at through that prism of who is and is not oppressed (more). Yes, the professor's opposition to an optional event could be taken as a whiny "but why should we reverse things", but his detractors' reaction, that rather than proving him wrong they'd make an example so nobody ever again dares object, was entirely out of place.
Of course, then since a-holes with an internet feed cannot just let this stand when it pops up on their "outrage of the day" feed, the college winds up getting actual death threats phoned in from the outside