I doubt that were review bombs. After the gallery "update" over 51% and maybe even more reviews were negative. Steam is just removing legitimate reviews of a legitimately terrible and lackluster game, that is a cash cow. Nothing new honestly. And Yes, those are literaly gifs.
Valve doesn't tend to remove thousands of negative reviews that happen in the spawn of a few days for no reason. It didn't help when like 90% of these was signed with pro China stuff, calling FOW for racist pigs etc. Chinese players made a big issue of FOW saying they saw no traffic data from mainland China, meanwhile the same players use vpn's to hide their traffic. They took that as FOW didn't acknowledge Chinese players/backers, and went all political about it. Even though further up in the post FOW did acknowledge their Chinese backers and appreciated them and their support.
No "legitimate reviews" been removed. You find negative reviews there still. Several thousand pro FOW reviews got removed alongside the thousands of Chinese ones. It turned into a cluster fuck of a culture war over a smut game. I guess all publicity is good publicity because FOW seem to came out on top.
A indy dev that creating a game called "Little Witch Noberta" got review bombed by much of the same people for much of the same reasons earlier in October. If you dig deeper into Steam about review bombing you will find more that suffered the same. I don't think the Chinese Subverse players earned themselves any favors doing this though.