Steam reviews are next to worthless when I'm buying a game.
I find them to be the most useful in games at least, thanks to the tooling you get from Steam to actually determine what is most likely to be true.
By it's very nature, if you look at an aggregate score, you won't get a full picture, and there are niches where scoring will always bias positive because of people eager to have the thing where they wanted it and dismissing core issues with the game (see many "anime" themed games in a variety of niches). This is relatively easy to figure out just by reading the reviews and seeing the context.
However, with recent and all reviews sections, the histogram of activity from the game, language filtering, steam vs key purchase filtering, account activity, hours played filters, community, news, and changelogs etc, you can get a really good idea of player sentiment and types of issues if there is a good enough cohort.
It's super easy in a matter of minutes to have a little dig and determine what is a rational review and what isn't, and how similar the trends are between reviews.
For Helldivers itself, you can tell pretty easily that a mass influx of negative reviews have come in, and you can easily tear into why. Whether it is relevant or not to you, is up to you alone.
Absolutely nothing new. Toxic, at least for the louder crowd (which is guess mostly social media).