You say this as though it's plainly obvious that it wasn't. The truth is that it depends, and not on whether or not we think his political views are ridiculous.

The causes of action in the lawsuit were unlawful termination on account of political activities (which are protected in California) and sex (which is protected federally). Google made three motions to dismiss and lost all of them. Does that mean Google is guilty? Of course not. All it means is that the claim stated by Damore, if true, could convince a reasonable jury that Google violated his civil rights.

Google would much rather pay out settlement money than risk having an unflattering jury verdict or have to release even more unflattering documents in discovery. I'm sure Damore would rather not go to trial if he could help it as well.

I'm not convinced it was because of his "political views" is an automatic fact.

People say "political views", that's how he might frame it, but I would assume Google would frame it as they fired him for making statements that women are less capable.

I feel this comment is a good summation of this conversation. I do not know whether you would agree with the presumed Google's opinion, but a big part of this entire "scandal" is that Damore never said that women are less capable.

Then they would lose because he did not say that.

It could be considered political in countries and political systems that consider women as second class citizens and bar them from holding elected office or other positions of responsibility, or if he was advocating for the adoption of such model.