What next? Is refusing doing business with Russia a war crime, too? After all, some civilians might lose their livelihoods and starve to death, right?
Also, Russia is relatively self-sufficient foodwise. There'll be shortages but no starvation. I'm sure though that if starvation was serious possiblity the West would exclude food imports.
Ah yes, because seizing Russian assets overseas is the same as "not trading with them".
Your bank account is held under terms. There are cases where freezing withdrawals is allowed.
If you wish to avoid that, you are entitled to store your money under your mattress (or use the latest crypto fad and be subject to absurd exchange rate variations).
Nobody was forcing Russia's ruling class to have all their money in overseas bank accounts.