No, it's not. He made the correct logical decision at the time, and the whole zero impact the unfortunate result had is behind us and has nothing to do with the present.
Expecting somebody to get fired over this is insanity.
People like you have zero idea what free speech even means. It doesn't mean you get to say stupid things based on chosen ignorance and not have your peers criticize it.
The best chance of getting them through waivers was then, when everybody is going through waivers and teams are set. Considering backups already have a limited role on this team, I don't know what else we would have learned anytime soon, and it would have meant potentially losing depth that we were more likely to need. Sparks actually won a lot of his early games that year anyway.
Comparing the 2015-2016 roster to the 2018-2019 roster is ridiculous.