It's important because right now everyone, OpenAI employees included, has no idea why Sam Altman was fired. And now we're being told that we may or may not hear the reason in 30 days.

What could the reason be that would justify this kind of wait?

I'll point out that Sam also doesn't seem to want to say the reason (possibly he's legally forbidden?). And all of the people following him out of OpenAI don't know, and are simply trusting him enough to be willing to leave without knowing.