why not? Private repositories, probably not, but open source libs/gems definitely.
Why would you support such a regime?
It would be a great place for pirate open source.
Well hosting a mirror from my open source project don't make me endorse any regime. I host my code in github and gitlab not because I endorse their countries. Your code being hosted there supports the local people there, developers that, like you and me, just want to survive and ship code.
The simple reason - you don't trust the host to keep your content up if it infringe's on anything deem it to infringe upon. 100% would never host anything up there.
Do you trust AWS? Azure? If you fear the state, the risk is the same. You can for example mirror your gitlab repository there. I think you are being to radical.
Way more than I trust the CCP. Not even on the same scale of trustworthiness.