She was probably being rude, but as someone who loves to sit and people watch (and stare, sometimes, too probably), maybe she was just curious. I always wear sunglasses when I sit and people watch so at least they can't TELL I'm staring at them.
Of course, I don't do it in a grocery store or someplace weird like that. Usually it's when we're traveling and I'm sitting stationary for a long time.

Maybe she thought you were an alien in your crazy bike gear???

But yeah, most likely she was just being a turd.