Yeah - probably a lot of folks that ride steel have gotten some guff from those that ride bikes made of Ti, Al, Carbon, Mg or Rearden Metal.

As for his position, I've read (on the internet, no less!) that aluminum frames can fail suddenly, though not quite a briskly or devastating as carbon is said to do. I wouldn't know as I'm not a metallurgist; maybe he was, for all we know. Maybe he was the East Coast Regional Shill for Rivendell.

Your taking the comment to heart is good in that is shows your genuine respect and affection for your machine. That said, try and not let it bother you too much - we all have our personal tastes, and they don't always align. I don't think he was trolling; I think he was simply uncouth. If being uncouth were a crime, then I'd be serving life based on the things I've said in my 20's and most of my 30's (I'm much more couth now, thank you).