In my opinion, the question comes down to “what is a valid criticism”. I think the bombing part, where a lot of people give a similar negative review at the same time is secondary.
If a game releases in a borderline unplayable state this warrants negative reviews. It shouldn’t matter how many of them there are and if they are all in a similar time frame. Same with an update that harms the game a lot. If this makes the game change the rating from positive to mixed or negative, I think that’s fair because if I buy the game now, I will get it in the most recent state and if this is shit I don’t care if it was better at some point in the past, I’m glad if I get a warning through the reviews.
If the game gets negative reviews because a person/group related to creating the game said or did something that a large group of people disagree with it’s more complicated. It boils down to if you can/want to separate the art from the artist and if you find that criticized thing bad in the first place. If you don’t think this is a valid criticism you probably think this “review bombing” is a bad thing.
I think the term “review bombing” is used to imply that the criticism has nothing to do with the game itself. But like with all terms, the usage becomes broader and broader until it changes or loses meaning completely.
Since Steam reviews contain written explanations it is easy to check why the game gets the negative attention. I never came across a game that had a lot of reviews for an unrelated thing where almost all the negative reviews lied and said it was bad for gameplay reasons.
Even if you cared about legacy, realistically, how many people are remembered for more than a few generations, if they are remembered at all?
Even the majority of the leaders of nations are only remembered by historians, people with a high interest in history and briefly by some students studying for their next test, and these will be mainly the leaders of their own country. Unless they did something exceptional good or bad.
And then there are a few exceptional high achieving writers, inventors, scientists and academics. Even within their field most become irrelevant and forgotten after a few decades.
Some ordinary people who did extraordinary things might also be remembered.
But if you compare that to the enormous amount of people who have lived and died, basically no one will be remembered after their death. I’m not making excuses for the bad behaviors of horrible people, I’m just saying that losing all relevance and not being remembered after death isn’t special.