The thing is that you don't get to decide what a legitimate complaint is for anyone (nor should Valve, why they have to step in and decide what is "legitimate" and "illegitimate" consumer feedback is beyond me - this always ends up as a slippery slope, just like "hateful content" and it's obviously a biased endeavour for the purpose of damage control from the start, since it's not going to consider any positive reviews as "review bombings" and just remove negative ones to boost review scores). If they bought a game that contained the color red too much, and they disliked the color red and complain about it, that's as valid a review as any other and the top reviews on a game's store page are decided by vote tallies, so if 50+ people agreed that there's too much red in the game and didn't agree with "John Q. Normie", that'll be at the top.
Good example of this happening here btw.:
https://store.steampowered.com/app/289650/Assassins_Creed_Unity/#app_reviews_hash
AssCreed: Unity has an Overall Review Score of "Mixed" with 61%, but lately they've been getting "Very Positive" reviews at 87%.
Why did this happen? Did they suddenly release some huge Patch that made the game (which was originally released in 2014) much better? Going by most of the late reviews it seems to be about UbiSoft offering the game for Free on uPlay and the Notre Dame nearly burning down, followed by UbiSoft donating to the rebuilding efforts:
Assassin's Creed Unity is currently free at Uplay from April 17th until April 25th
Thanks Ubisoft & Assassin's Creed Unity for giving us an opportunity to appreciate what Notre Dame used to be.
God bless France.
Reconstruction of Notre Dame
Worker A: Do we need to build this catacomb?
Worker B: I don't know, Ubisoft painted it on the drawings.
Ubisoft just said that this game is free for one week according to what happened with Notre Dame.They also donated 500'000k eur.
this game is free in the ubisoft store until april 25th
Does anyone think their fancy "off-topic review activity" algorithm will kick in in this case? Fat chance, which makes it a de-facto biased algorithm for the purpose of shilling and boosting positive review scores while only being used to filter negative customer opinions and sentiments and shows that in reality it's got nothing to do with "off-topic reviews".