Why are people inclined to comment on the sound of the oboe as if it's a bad thing?

The high schoolers get out of school fifty minutes before us. Today, the high school All-City results came in, so a bunch of high schoolers were at band and Mrs. Neu was giving them the music for All-city. For one of our songs, the oboe part has mysteriously disappeared (or the composer didn't write one!), so I end up with a flute part. Which would be fine. If I played the flute.
  One of the high schoolers walked up behind me while I was playing the aforementioned song and was like, "You have a flute part." I told him that I knew that. He said, "Well, you sound like a flute," and I was extremely insulted. That is one of the rudest things you can say to an oboist, almost as rude as (gasp) "Is that a clarinet?" No offense to all you clarinet and/or flute players out there. And the flute and oboe are VERY different looking. The flute is entirely metal (with the exception of a little cork) and is held horizontally while being played. Oboes are wood or black plastic, and are held vertically while being played. And besides that, they have reeds. (Go reed instruments!)
  And the moral of this story is... make sure you know what instrument someone plays before you assume it's a clarinet.