[ciex]

Legally, yes. Morally, no, they can't do what they want. Users have invested time and effort over literally decades to build today's Reddit communities. Therefore, Reddit needs to give good reasons for substantial changes they make if those could be harmful to community health.

[storkhm]

I think this is a huge stretch. I would have a hard time even calling it immoral if the whole site vanished tomorrow, without reason.

Surely, there is nothing in writing that has been agreed to that Reddit owes anything to the health of communities.

No one could possibly say this about usenet and I don't really see the difference.

[HKH2]

The law is enforced top-down whereas morals are enforced bottom-up, so good luck trying to enforce morals with people who think their individuality matters more than anything else.