In addition to the causes you list, I'd add that education has become increasingly politicized (in the extreme). To the point where many new graduates are either activists or reactionary from having been steeped in that environment for at least the time they were in higher ed.
That's pure speculation based on your own views and experiences. What you probably noticed, is the visibility into these people's lives that you or others did not have prior to social media and 24/7 connectivity. Universities have always skewed towards the left side of the spectrum, it used to be called liberal arts educated, today the right has successfully renamed it as indoctrination.
It's not speculation. "No platforming", "safe spaces", "trigger warnings"... are all relatively recent inventions. Universities have always been left leaning, but the "moral grandstanding" mentioned in the original post is a more recent development.
I agree that those are all terrible as well! The reason I don't think they lead to "moral grandstanding" that we see discussed in the OP is because they were fundamentally outward focused, in that they were meant to accomplish something (misguided and pointless as they may be). Whereas the items I list are very much about in-group signaling. Hence "grandstanding".
No platforming, safe spaces and trigger warnings are all outwardly focused. Especially no platforming and trigger warnings.
The dynamic within christian groups that leads to a the things I described all have considerable in-group signaling component.
Also, some level of that in-group signaling is functional - people don't just randomly take coordinated actions like that. The signaling component is likely necessary for the organization to happen.
