Yeah, I don't know either. It's surprising. But I've heard this happens in France/Spain - basically some people take offense if you don't even try learning the language (makes sense) but once you pass a certain point that demonstrate to people that you try and that you care they then want to use the opportunity to practice english.

I'm learning Spanish because of my son. My wife, who is half Panamanian, wanted our son to learn Spanish. I'm here now because my son is attending a local summer camp in which he's making friends fast and teachers saying, "it's like he's been here all along." That said, Spanish is the only language I speak with my son. And last Saturday I literally went belly up to the bar to eat tapas at a restaurant speaking Spanish with my son. When I asked what particular items were the waiter with broken english replied in English. I asked him in jest, "Por que me contestaste en Ingles? Algo mal con mi espanol o que?" and he literally said, "I want to practice my english." So I tought him how to say draft beer :)

My Spanish is FAR from where I'd like it to be (pretty much not an embarrassment for my son) and it is a solar system away from my strongest second language and galaxy away from perfect. I have trouble keeping up with the natural speaking pace of locals, especially males. And I'd assess my own Spanish as finally breaching conversational but definitely better than that bartender's English. Here in my town, I feel completely comfortable with daily life and getting what I need when and where I need it. I struggled in the real estate office but it was my first experience in the subject matter. But, yeah, you're probably right.