People would become like walking zombies, agreeing on the same things.

This and your Star Trek analogy imply that it's a forced-upon agreement rather than people coming together in their views and recognize their differences. You seem to think that I mean people to agree upon every single matter, which is taking my argument too far. I don't believe that this is agreement: this, as you point out, is zombie behavior.

We experience reality differently due to the massively, incomprehensibly-vast amount of ways each of us brought up. Every detail shapes our view, and so it would be quite difficult to have people to agree on everything, much more useless. There are, however, things that would benefit from such an agreement: like, say, agreeing on not using derogatory terms towards people because they're belittling to the target person and don't address whatever issues you might have with their race, ethnicity, nationality, sexuality or another aspect of their lives. It's a can of worms I don't want to open; I was merely providing my perspective on why that could be in the works.

As for "anything's possible" argument: thank you for noticing that. I will give it some thought. If there's any other insight you can provide on the matter, I will greatly appreciate it.