Sometimes, asking about the camera model can be just an innocent conversational filler.
It might be the person who was asked was a bit too sensitive and hung up on camera brands himself and thus interpret the question in the wrong manner.
It may be a conversation starter... The general population may not be familiar with photography, but they know their cameras!
I used to ask the same question before just to start a conversation.
I guess the safest question is to ask: What type of photography are you in to?