How to misunderstand the situation 101: bring the first amendment into the discussion when that’s not what the discussion is about.

Let me break this down for you: you host a weekly poker night. My buddies and I come and during these nights plan a crime. We than carry out a crime and get arrested. The investigators come to you and ask “what did those guys talk about at your poker nights?” You say “poker stuff”. They subpoena you to get a better answer. Where in all of this did the first amendment come into play?