It's actually fairly common for managers to get let go with a week or two left (or a month or two left, if the season is completely lost). And you're also sending a message to the fans and players. I'm sure that the relationship is such that it wasn't a big deal, or a big surprise. I doubt Kapler was like, "WTF, why can't I manage the last two games?" If you're not wanted, you don't want to be there, and his paycheck is gonna clear (for all of next season) just the same.
I mean, if we're really going to get outraged on behalf of Gabe Kapler because he was endlessly jerked around by the team that fired him when he still had a year left on his contract, let's go revisit 2019.