You could of course extend this scheme, and construct all sorts of scores - such as a "liberal-conservative score", with whose help you could block anyone whose political opinions are insufficiently close to yours. That would be a very bad idea, in my view. Scores of this sort should only be used to combat harassment, threats and other forms of anti-social behaviour, and not to exclude any dissenter from discussion.

You give people a tool to build echo chambers, they will build echo chambers for themselves. Your views on what constitutes a "bad idea" would be irrelevant at this point. Not to mention that many interpret the existence of people "whose political opinions are insufficiently close" as harassment and threat by itself.