This particular test might be reasonable, but at some point you're just filtering out anyone who's not in your bubble, which is a problem when your beliefs are extreme because your bubble is tiny.
Imagine a Marxist who refuses to discuss economics with anyone who can't explain dialectic materialism or enclosure.
Even in his particular test, he's filtering out people who are quite well informed on political topics but also feel that the input of the average person has effectively 0 impact. And this is quite a huge blindspot because political understanding/knowledge tends to precisely trend towards that worldview for many. A sack of money goes much further than a phone or picket.
IMO. It is ok to filter them out.
One simply does not have infinite time and resource to engage with everybody.
Aware what you have filtered and don't treat them like idiot