The problem is after it changes owners through exchanges and tumblers. It's like stolen cash being deposited into a bank and given back to someone it was stolen

The problem is after it changes owners through exchanges and tumblers. It's like stolen cash being deposited into a bank and given back to someone it was stolen from 5 years and hundreds of transactions before. It wouldn't be fair to anyone if we did that with cash, and it's not fair to try to enforce that with bitcoin.