Though police are bad even in video games. If somebody wants to be a jerk that is there right.
No, its not. Read Rousseau's Social Contract if you would like to understand why it is not a right. Behavior within a group needs to conform to societal norms, or you risk creating all kinds of problems.
Verbal abuse can even be prosecuted under assault laws in various jurisdictions.
You are right that thought police ARE bad, in any instance. No one should tell you how to THINK. However, "action" police are useful. Go ahead and think about how cool it would be to steal a million dollars from a bank... no harm in that. Actually do it, and you will--hopefully and most likely--find yourself in prison. Thoughts are your right, actions are your responsibility.
If you think someone is an idiot, keep that thought to yourself. The only value in saying it is to make yourself feel better/superior than that person. That's it. It is an entirely selfish behavior, with no value to anyone but you, and potential harm to the other person.