Review bombing is nothing new. It happens mostly when games release patches that break more than they fix or when a game decides to use Denuvo Anti-Tamper software with a game on Steam (DRM within DRM). These tend not to make the news much unless there's mass fan hysteria surrounding them. But recent Negative reviews on DotA 2 for Half-life 3 not existing and now Firewatch being review bombed (albeit to a much lesser extent) over the PewDiePie incident, have given Valve both the cause and PR blanket to release a new feature they have been working on "for a while now."
In a new announcement on the Steam Blog, Valve has simultaneously revealed and rolled out review histograms, which give prospective buyers a better understanding a game's real review value. The graphs provide a visual representation of the types of reviews (positive or negative) were given to the game and when so that if there's an abnormal amount of negative reviews all of a sudden on a game that was predominantly positive, you'll have a better indication why.
For example, here's the graph for Firewatch:
As you can see the gold banner at the top gives you a heads up on the "High Volume of Negative Reviews" that have come from the PewDiePie incident. It gives you the ability to filter out only the Negative reviews, so you can get a quick and exact idea of what the reviews are criticizing the game for so that you can make your choice whether or not they are viable.
Review bombs will continue to happen for one reason or another so long as the general public has a direct line of communication to have their voices heard. But, at the very least you can now make more informed decisions, no matter what side of the argument/fence/political spectrum/etc. you sit on.