Why do some Americans think all people from Spanish-speaking countries are Mexican?

I don't know any American who thinks this. Spain is actually a country in Europe thousands of miles away from Mexico. Anyone who thinks a Spanish speaking person must automatically be Mexican has no brains whatsoever

90 percent are mexicans & either way I can not tell the difference but DO I just assume ALL are mexicans? No.

People assume this because they're ignorant. And it's true many people do this with Asian people including appearances. They don't want to accept they're wrong and that the world is larger than they think.

Some? None do, unless they're three years old, and get their knowledge from a few comedic, childish television shows, which rely heavily on stereotypes to be funny. Mexicans are the vast majority of Spanish speakers in this nation, so it's reasonable to conclude that, the majority of the time, a Spanish speaker is of Mexican descent, though. That's simple logic. Claiming to know what people think is pure ignorance, though. Don't stoop to the level of the insecure n!ggers in this section. Edit: Look up the definition to the term irony. No, it's not ironic. Now stop playing the victim roll, you whiny little girl.

The south, maybe. There are some pretty stupid people down south. But up north, we won't know where you are from unless you tell us. We don't generalize all spanish speaking people as Mexicans. But I can't tell a Mexican speaking Spanish from a Spanish person speaking spanish. I can't hear a difference in accent. But I think Mexicans look a bit different.

Sorry to say it but majority of the North American aka USA is fueled with ignorant and stupid people. If you wondering by now, how did they manage to be so rich and powerful? the answer is they follow the selected few 1 sheep lead 30 lamb!

To anyone who denies this: I was on a website where the language options were labeled by the countries' flags. The Spanish language option was the Mexican flag.

Because Mexico is the most popular Spanish speaking country....They do the same thing with Asians....They're "Chinese" to some people because they're the most well known.