I'd like to clarify some of my thoughts. I think allowing people who have false doctrine (what the speaker was actually talking about)into our homes is a no-no only depending on the potential influence they may have on our kids (I know I don't have kids.) Most of all depending on the particular individuals approach honestly I avoid people with "sound doctrine" if their approach is cold, arrogant, and hard.
If someone is set in their ways and has an agenda to instill their "false doctrine" in you, sure, avoid them.
it was interesting, something the speaker said, "the question 'is Jesus God or not?' will make all other questions unnecesary." I can totally understand someone who is not convinced that jesus is God. We all should struggle with this at times anyway. The scripture segments that are most often used to argue the deity of Jesus are not saying anything about Deity. The "Son of God" verses and the "I and my Father are one" verses are messianic passages not Godhood passages. So to me I could have a completely normal spiritual relationship with someone who doesn't think Jesus is God (even though I myself am convinced of that).
approach is everything.
If ideas are shared sincerely and with understanding i have no problem being hospitibal. Don't avoid anybody just cause they disagree with you or have false doctrine. If they hold "false doctrine" work it out together with them and don't allow dogma to get in the way of a much more important concept, relationship.