Fear is a good answer here, though phrases like "helicopter parenting" and "victimhood culture" might bely some existing biases by the author. Perhaps the fear of the "other" tribe are driving these shifts; after all, I doubt that anyone who says they'd be in favor of restricting speech feel like their speech will be restricted.
And it's also possible that a decade or so of gridlock is taking its toll. If this is what freedom looks like, could you blame someone for wanting to try something different? Not saying that's true of me, but I can see how it would happen.