Sam is admitting it now for two reasons:
1. He wants to make it sound like not IPO'ing is actually the rational thing to do 2. He wants to throw cold water on Anthropic's IPO in a few weeks
Number 1 is just spin. Number 2 makes it particularly nasty. Your opponent offers a fig leaf and you turn around and underhandedly try to sabotage them?
Sam doesn't have many redeeming qualities in my book. Just an atrocious, rotten person with a friendly personality.