I don’t know anything about either of these people or the nuance of their professional qualifications, and I think that probably also holds true for 99% of other people who will see your comment.

A bit more context might be helpful.

"For an institution that had historically promoted from within, first with Sam Altman, now CEO of OpenAI, then Ralston, the Tan era came as a shock. Within YC, many staff had wanted Michael Seibel, the cofounder of Twitch and YC’s longtime batch leader, to get the job. Multiple sources remembered longtime partner Dalton Caldwell vocalizing what others were feeling, too: we’re all just employees who work here, message received. Seibel, meanwhile, wrote a letter to YC’s board to explain his disappointment at being passed over, despite broad internal support. He vowed to support Tan moving forward, anyway. Caldwell and Seibel declined to comment on those incidents through a YC spokesperson."

https://www.forbes.com/sites/alexkonrad/2024/03/08/inside-ga...

https://archive.is/a4Tno#selection-615.0-623.266

Wasn't he the CEO in the past? I see him referred to as "CEO" in some places, like [1], but I can't find any announcement or news article about when this changed.

1: https://techcrunch.com/2020/03/16/yc-ceo-michael-seibel-open...

what has Michael Seibel done?

Why is truly hard to believe a fact, or two?

Last I heard, facts don't have to be believed; they just exist.