His example for comparison was rather distasteful, but you did reinforce his point. It's name calling with the intent to insult. And while many people present valid information and construct good arguments while doing that, casually insulting your opponent, or worse uninvolved bystanders is bad manners.

You can just say 'racist', or 'person who relies on outdated ballistics information'. No need to have one derogatory term to lump the two in together and then sling in around casually.

People say that 22lr is the 'deadliest caliber' because it is the caliber that has ended the most lives in the United States, that being because it is by far the most common. The original source for that was a study done in ~1970 but there have been others to back it up since.

I'm not going to go so far as to say that _no one_ ever has said that .22lr is more lethal than any other caliber, but it is the exact opposite sentiment of "I use a .45 cause they don't make a .46" so it's not likely to be a person from that group saying it.