It's neither difficult nor arguable, but it's a bit of a cop-out. Google is, of course, well within their legal rights to fire the employee. The 1A applies only to government restrictions on speech.

But the larger question, of whether it is good that a particular political ideology, adhered to by a small minority of the country, should hold such sway over public discourse that to challenge any of its dogmas is to commit career suicide, remains. This is a trend that is only accelerating, and it's going nowhere good.