Because this wait has gone from building hype to building frustration. Nintendo should not have done Jojer first of there were all these stipulations surrounding him.
We don't know everything (or hardly anything) regarding his release or what Atlus's involvement is. It could be that the release was initially planned for March but due to late development problems in P5R/P5S, Atlus had to delay and thus so did Nintendo. Or this was the plan all along and Nintendo didn't think waiting four months when we already had the goddamn game to play was a big deal.
Maybe it's just because I'm old and have other obligations that keep me from browsing the internet for gaming news all day, but I really think everyone is blowing this out of proportion. He's a single DLC character. We already know he exists. He'll be out eventually. Chill and enjoy the over 70 freaking characters we already have.
When he's out you're all just going to jump onto the next hype train the same way and we'll do this cycle all over again.