Willie, why would you say anyone who doesn's know shouldnt participate in the hobby? That is not an objective fair statement.
I carry a COLT LE6940 as my primary duty rifle and I am very proficient with it. I think it is a legitimate question to ask if a reciever is marked .223 on an older AR-15. I own four black rifles and only one is stamped .223 Definately worth clarification since there is a difference in the two rounds. So happens that my CAR-15 is a lightweight barrel with a lightweight cut out bolt carrier, so I wanted to be sure I was good to go and would not damage the rifle. Now I know thanks to some helpfull folks here!
Glad your not the only one providing info here because in your book, I should not own a gun!
May God make smooth the path you follow!