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

Well, the contention of TFA is that you will turn ideologically crazy if you have an extreme belief and only speak to average people who disagree with you.

Turning ideologically crazy sounds like something that would also happen if you only talk to people who have the same extreme beliefs.