Why do you need to discuss anything at all? Work is where I work. I'm being paid for my time and professional expertise, not my opinion on anything else. I don't get why would I be allowed to spend that time on conversations not related to work.
Being allowed to have some short talk, maybe discuss something quickly, like a game last night or something, is and should be more of a nicety. Nobody gonna stop me from doing this. But I don't see why we should be allowed spending long periods of time discussing other important issues.
There are meetups, we can get together after work, go for a beer etc... And have those conversations in our personal time if we deem it important. But not during business hours.
Work is for work. So banning conversations is reasonable imo, and not only political.