I haven't felt comfortable speaking at even the few al-anon meetings I have attended because it isn't always clear what is okay to say and what's not okay so I am afraid of breaking some "rule". I think that totally stinks that you were approached like this! If that's the rule, they should make it clear at the beginning of the meeting rather than pull you aside. How is a newbie to know?! Pulling someone aside just makes a person feel bad, no matter how tactfully you tell them they were wrong.
SP's meeting sounds lovely! or you could collar someone after the meeting and say - I'm NEW! I don't understand what I can and can't say, I don't get the format! please help, and most people will, because they were once new and scared and didn't have the foggiest idea what "cross-talk" is either! In the group I went to, any new-comer was given an enormous amount of latitude with this until they had started to share, started to find their feet and get some of the pain and fear and anger out, because that was seen as more important than the rules (unless someone was seriously overstepping the mark).