The only person I've seen with sensible answer to this "Why are they doing this?" question is the Z Man. His take is that this is a religion and that these people are True Believers, each eager to outdo the others in their displays of piety. It's a religious hysteria that's eroding our civilization to the point of collapse. The point is to turn the world into such a shrieking madhouse, to make the the common folk so miserable that they eagerly embrace whatever new, stable system the big brain expert rulers impose upon us. I won't call that new system "communism" because that term doesn't do it justice. It'll be much, much worse.

But the silver lining, the upshot is that these leftist revolutionaries never think things through. They're good at tearing down systems, they're shit at creating new ones. They always insist that reality obey their models and theories, and anyone who points out that the theories aren't working is punished. Their systems always run on fear and lies, and ever bigger lies are told to paper over the previous ones. Such a system saps the motivation of everyone at a production level and selects for laziness and ineptitude. This means that the system will become increasingly vulnerable as time goes on and opportunities will present themselves.