Can this SCOTUS ruling on USPS discrimination affect mail-in voting?

Moderating:

Since this is about mail-in voting specifically, I think this is more P&E than GD, though the rules for both are identical. I’ll shove it over to the sister forum. In addition, we already have a P&E thread about the SCOTUS ruling that was started earlier:

For general discussion on the topic. For the moment, I’m not merging the threads, because this one, per the OP, is about possible ramifications for mail-in voting, a much more specific topic. If it’s general discussion, please use the thread mentioned above. Or, if @Czarcasm prefers, I can just merge the threads.