I worked at Google for quite a while, 2005-2013, and even then, the internal political discussion was pretty toxic, but a lot smaller in scope since there are far fewer people.
There were definitely groups meant for discussing politics, and loudmouths like me willingly participated in those - however, it was very uncivil. There was a majority view in the company, and if anyone didn't agree with the majority view, the majority engaged in heckling, ridicule, etc. It was already becoming an echo chamber, and as the majority grew, their tactics grew more petty and vicious. However, this was expected in the politics groups, and you knowingly entered that fray.
What seems to be happening a lot lately is that politics are spilling over into large, global mailing lists which target a whole geographic region, so many people get involved, and when a company has 200k employees and contractors, you will find some outliers in there who will pick nasty fights.
It only makes sense that they're cutting down on something that has turned toxic. It's a bit disappointing to hear, since I personally enjoyed the occasional, honest discussion with smart people of other viewpoints - these good discussions made the much larger number of ridiculous ones, bearable.