It would be very concerning (and in violation of the First Amendment) if the government forbade you from talking about politics at work. But this is not that — it's a company saying that at their company, they don't have political debates on their internal communication systems. This is different in both degree and kind.

Are you concerned that if too many companies take this approach, it will become the norm, like it was before about 10 years ago, and that then there will be attempts by politicians to codify it into law?