That depends on if the astronauts' return mission was delayed by the previous regime that controlled NASA. It seems like a pretty rational (if unethical) move for Biden's team to attempt to delay things to avoid giving his political rivals a big PR victory. Honestly though, any conversation to that effect would have happened behind closed doors and I doubt that even Musk knows exactly why they decided to delay things.
As far as I know the political regime of the USA was a democratic one last year.
The PR victory of a returning two astronauts (one of which called space her "happy place"[1]) who didn't take the ride home on a leaky capsule is rather minute and not worth a movie like the Apollo 13 mission. When them staying up longer NASA actually might have gotten more stuff done than if they didn't, even with Crew 10 starting with two empty seats in September.
The whole thing isn't as bad as Trump ordering the release of water in Northern California, but once more it shows that he wants to things purely for show with no regards to the consequences.