The massive influx of new ratings could also simply be linked to the fact that the game is included in this month's humble choice, adding a ton of new players
I'm not sure it qualifies as "reverse review bombing" if the recent review +/- percentage matches the all-time percentage. There's just more reviews because of the shutdown, the ratio of positive vs negative hasn't meaningfully changed (97% positive overall, 97% positive recently).
Does review bombing have to be negative? For me it was always a big pile of reviews in a short time, like dropping a bomb, but without inherent rating.
It can directly affect how many people will buy the game in the future on PC. Might not be a huge number, and maybe it look like kids throwing a tantrum, but as long as it takes out any ammount of money from MS pocket Im all for it.
Edit: nevermind, its positive reviews, I did not pay attention.