Yes man, it is a defense. When someone is criticizing SCOTUS for acting quickly on one case to help Trump and delaying as long as they can on another case to help him (particularly when the one they acted quickly on was actually a question of first impression and the one they're delaying is not and was already addressed to any reasonable judge's complete satisfaction by the appellate court), pointing out distinctions between the cases (which will literally, 100% of the time, always exist) as an alternate explanation for their delay is defending them.
And I really don't know how to express how much I hate the "who cares? It's not like it would even matter" mindset. I'm pretty cynical about the American voting public, particularly undecided voters, but I do think there are millions of undecided voters who would decide for sure they won't vote for him if he were to be convicted of crimes related to January 6th or of stealing nuclear secrets. They're still undecided for hundreds of reasons, but particularly because they don't pay constant attention to politics and thus don't really know much detail about any of Trump's million scandals. They don't know what you know.
The Republicans on SCOTUS know this. They know delaying their decision on immunity, and then punting back to the district court for specific determinations as to whether all of Trump's acts at issue were public or private acts, will delay the trial until after the election. They are very fucking clearly doing this because they do not want undecided voters to see him get convicted of Jan 6th shit or of stealing nuclear secrets before the fucking election! For you to brush this behavior off as insignificant reveals a deep disdain for American democracy, the same disdain they have.