I think the main issue here is we have seen a large amount of review bombs from niche groups tanking scores for shitty reasons and there is a very obvious reason people are upset at the very mention of the term.
I also think your OP wasn't very well researched or presented. Had you, perhaps, taken a deep-dive into examples you'd consider justified and made a case for enough to show that the phenomenon can be a valid symptom of anti-consumer practise and consumer frustration etc... then, maybe, people would have been more open to the debate.
As it stands, we see a LOT of entitled bullshit online. We have seen some prominent examples of review bombs being used by shitty people. We also see examples of niche groups with legit concerns take to reviews to tank score over a single issue. There are also cases like AK where people were naturally leaving negative reviews due to the poor product... but that the community was actively rallying each other to get involved... people who wouldn't have left a review normally, but do so because they have been convinced to use their voice to make an impact. And examples like this will muddy the water on what a "review bomb" actually is.
There is a conversation to be had here, but I think the "ethics of review bombing" in general is probably not the way to frame it. Instead, it would be to look how it can be symptomatic of other issues, and to ask "in these specific cases, is this justified?".
