In your last sentence are you admitting these camps exist as described and the only alternative solution is bombing them? How about a third option- neither bomb nor enslave.
This is a big reason for Trump’s appeal - being able to rally behind someone who can so effectively withstand constant derision from all directions. Moreover, the apologists on this site and elsewhere will continue to excuse this behavior until they are backed into a corner and enclosed into a tomb of their own making.
Why is it happening? Because they can. And we are making it increasingly easier for them by building these centralized, mostly open platforms like Facebook and Twitter.
There has been no collapse in the intellectual life of Americans. If anything maybe a peak then moderate decline. The only difference is these platforms.
By what mechanisms could Russia and China influence the US a few decades ago? Substantially more limited.