He worked at Blizzard, but not as a developer, it’s been likened to someone who worked in the billing department at a hospital weighing in on medical care.

A QA would probably be more involved, since they would be testing the game or something related to the game. How relevant his experience was depends on what he worked on and who he had access to talk to. I learned a lot about electrical engineering while working as a software engineer at a company that built custom antennas because I talked to the EEs a lot. I wouldn't be surprised if he had a similar experience at Blizzard.

preferring the ego boost of being a streamer

And probably the money. With a big enough audience, it pays reasonably well. I doubt his games are selling well enough to live off of.

He claims he was review bombed

He claims the other publisher was review bombed, I'm talking about his studio's games, which do seem to be review bombed (overwhelmingly negative for recent reviews, positive all time).

I think a lot of people who are mad at him were following him

Perhaps. But a lot of people knee-jerk join the bandwagon as well. Look at everyone jumping on the Godot hate train. I refuse to form a negative opinion without being fully informed, because the cult of public opinion can be absolutely reactionary.

So I err on the side of giving people the benefit of the doubt.

And yeah, content creators jumping on the bandwagon isn't my cup of tea, since they have a motivation to exaggerate to get views. I want a pretty unbiased, fair take, not a rage bait take, and that's more likely to be found on a forum like this instead of on YouTube. Hence why I'm asking.