And what's wrong with thinking a Hispanic person speaks Spanish?
Tony. You have a heart of gold, and I truly believe your moral compass works just fine. You've made some great points. But I wanted to weigh in on this, mainly because it was a bit of learning curve for me.
I live in the Denver Metro area, large Hispanic population. Now, it took me some time to realize that Latinos can be (A) ESL (English as a second language), or (B) truly bilingual (learned both from early childhood, perfectly fluent with no accent either way), or (C) Born in the USA, English is their only language, and they couldn't tell Spanish from Martian.
So if you want to know which it is, you have to tread lightly, be sensitive, and, rather than assume they speak Spanish, eat tacos every day, and drive a low rider, ask, "Do you speak Spanish?"
An accent is a good sign they speak English as a second language. No accent? could be B or C above.
And if they are ESL or bi-lingual, I make it a point to tell them I envy anyone who can speak more than one language, it's a great skill. I also ask, respectfully, where their parents were born, and if they speak English. It's a real eye-opener to sometimes find out the family line has been born and raised in the USA for several generations, and only the great great grandparents spoke Spanish.
This is all designed to avoid sounding like a racist gringo. Just based on this alone, I make friends with Hispanics really fast and easy, they appreciate my sensitivity and interest, and they proceed to laugh at my broken Spanish.