Plus, at least from my perspective, Activision-Blizzard was already bad enough that if MS made it worse, it wouldn't affect me because they were already bad enough that I'd swore off their games. MS owning them was an improvement or at worst more of the same.

That's absolutely not the case for Valve. They are one of the few large companies that I respect plus they are playing a big role in breaking the windows stranglehold over OSes when you like to play games.

The level of popular opposition to MS acquiring Valve would be on a whole other level than the opposition to the blizzard acquisition. It might even rival the opposition to Nvidia acquiring ARM.