He said he was drunk when he posted the rant calling for slow death of most of the San Francisco city council, so of course he didn't send it to corporate PR to check. This kind of behavior shouldn't be acceptable for the head of a respectable corporation, even if his tweet hadn't led others to follow up with death threats. He should resign or be dismissed and YC should replace him with a responsible adult. This isn't a minor offense, it is grotesque. If he remains, it reflects very badly on YC.