They don't seem afraid of activism if it's protesting the current bad thing.
They won’t get denied tenure for protesting the current thing. It’s more likely they could get denied tenure for not loudly protesting the current thing.
As the sibling notes, academics have no problem suddenly finding their voice when they discover a colleague who's secretly harboring mildly right wing views. The open letters, protests, outrage and demands for resignations flow like water until the administration folds, usually about 0.25 seconds later.
The author describes a problem created by the policies of the university leadership, but refuses to lay the blame at their feet. Instead he/she says things like "This is not an educational system problem, this is a societal problem" and "It’s the phones, stupid." after describing a problem that is 100% caused by the faculty themselves. Because where do the deans come from? Why would they have leverage to dismiss a professor who upheld standards? They came from the faculty, and they have leverage because the faculty created this problem and are willing to propagate it.
They care about things like the US News and World Report rankings, and if students are failing classes and it starts hurting their graduation rate and hurting their ranking, they put a stop to it.
He did say it, but you have to keep reading after that. Fail too many students and you will get called in by the dean for a "discussion" where they basically tell you to stop doing that. For the non-tenured faculty this is not something they can reasonably fight. Maybe tenured faculty could, and they might not get outright fired, but their teaching load could be reduced or students will simply not sign up for their classes once they have a reputation for being a hardass.
Aside from that, nearly every student manages to have some "disability" that requires an accommodation. I had one professor friend tell me a student required an accommodation that they not receive any negative feedback. They literally weren't allowed to tell the student when they were wrong.