I'm definitely ambivalent about this move from Namecheap. I'd be curious to know whether this decision was made unilaterally by Namecheap's US-based CEO or whether it was pushed by their Ukrainian employees.
While Namecheap are understandably angry about the Russian invasion of Ukraine, I'm skeptical that cutting of their Russian customers will do anything to help Ukraine. If anything it will only cause Namecheap to lose revenue and thereby force them to cut jobs in their Ukrainian based workforce. Long term it also creates reputational risk for Namecheap as a company that makes decisions based on short-term political factors.
Requiring Namecheap's Russian customers to transfer their domains to another registrar in the next week is also easier said than done given the financial sanctions against Russia will probably make it much more difficult for them to pay for transferring the domains to a different registrar. I think it's safe to say that the average tech-savvy Russian is probably more anti-Putin than the average Russian as they have to jump through hoops and mess w/ VPNs to access western based services such as Twitter etc. So in practice this move might lead to de facto censorship and loss of income for their Russian customers, many of whom would be against the war.