Yes, I mean Polish people, who until fairly recently were an ethnic minority in the Soviet Union, and treated quite badly. Watching what you say due to fear of secret police is something that remains a very real memory there.
In any case, the point here is that if you want to be accurate, you'd be wise to say non-white American.
Try and adopt a non-Amerocentric viewpoint, at least around here.
With the way you worded it, yes, that's what he/she thought, and I cannot blame them for that. If you're going to debate someone on such a hot-button issue, you need to be clear. Otherwise I open the site and see almost an entire thread being reported because there just seems to be people fighting and getting nasty with one another. Then that nastiness looks as though it's going to start getting spammed across the front page.