What's all the fuss about polka? Isn't it a Czech kind of dance?
In the US "polka music" doesn't refer only to the rhythm known as 'polka' but is colloquially used to describe any music from Germany/Czech/Poland with any kind of traditional elements, especially if it's a dance rhythm and has an accordeon in there somewhere.
It's also used to describe music from North Mexico/Southern Texas with similar features (adopted from 19th century German immigrants).
youtube.com/watch?v=28iVOoBStyY