So I guess the way I presented my argument was misworded; I meant more of what @IdiotWithPencil had said about being empathetic/willing to listen to someone else about what they're interested in, as you would want someone to do the same for you if need be. 
Would you talk about cats a dog park? Sure, you love cats, but it's a dog park. Keep your discussion focused on dogs. Though with this example, you have to ask why would someone intentionally put themselves in a situation in which they're the odd one out? EDIT: Somehow, this relates to our discussion, I swear...
So I guess I'll wrap this up with the orignal question: Does art make you square?
IMO, it depends. I love illustrating and on my freest days, I'll spend hours just designing characters, or brainstorming, or writing a paragraph here and there, but I think it's healthy for creatives to have a balance of interests. You'll often find more inspiration to fuel your creative endeavors, and you'll have productive alternatives for when creative blocks hit. 