They did allow ETC withdrawals after the fact: https://support.coinbase.com/customer/en/portal/articles/252.... I'm not sure this is a matter of difficulty to implement.
- If BCC really goes to zero, nobody will care and it will fizz out.
- If BCC has value, users can benefit from that value like the rest of the ecosystem.
Frankly, I don't see how what they're proposing is even legal.
That said, Coinbase has played the regulation game better than anybody else (they're the only entity allowed to sell cryptocurrency in New York last I checked) so credit where credit is due.
Unless of course Coinbase plans to run away with everyones money long before the class-action suit is filed.
Because they also want to make a statement to influence the viability of the forked coin.