So? Does it make the other guy come back to life?
Not killing your own men when they fail in unusual situations they weren't prepared for is completely normal . Thrawn doesn't deserve any praise for that.
Vader at least did his cleaning in the top of the command structure, killing people who were actually responsible for failures.
He dies because he says "What happened wasn't my fault" instead of "I failed and need to learn how to deal with these situations". The crewman exhibits a behaviour suggesting he doesn't want to fix his mistake, thats what Thrawn doesn't tolerate, not the failiure itself.