Oh no! The whole, Hispanic debate! This could get ugly! Actually, Hispanic really refers to people from Hispanola, which was named such by the Spanish settlers... so although it goes back to europe, if you really want to get into the correctness of it all, Hispanic is not correct for Spaniard.
This is a hot topic.. and a lot can be said about it... but I'm not going to get into it. As far as people, mainly from the US thinking that all Spanish people look like Mexicans... well, since with all this Politically correct nonsense started for a long time everyone used the term Spanish to mean anyone from a Spanish speaking country. Since the USA is neighbor to Mexico and it is a culture very mixed into the fabric of the US, well, its no surprise that there is a confusion!
When someone asks me what I am, and I say Spanish, its usually followed by, so, where are you from?! I love that!(sarcasm here) So I usually have to give a bit of a geography lesson and explain why I'm not 'Latina', or really hispanic for that matter, but I usually don't THAT technical.. especially since in modern times, it seams that "Hispanic" is most widely used for Spanish-speaking.
I've found though, that most people are just lacking information, or are confused... but are pretty interested in finding out the answers
Oh, and redheads in spain.. there aren't many, but yes, mostly in the north.. but it doesn't have to do with having gypsy heritage, but the fact that they come from a region not as affected by the roman, morrish and other invasions. Truth be told, waaaaaaaaaaaaay back when, the norm in Spain was blonde or red hair! Those of us with dark hair are a result from a whole lot of mixing and intermingling that went on!