Laugh if you must, 2 weeks ago, I played a NH and theme was Pennsylvania Day for which they requested a polka party. Very happy music and most of those old-timers were glowing. Loved how animated and responsive the audience became. Haven’t done a polka gig for about 50+ years, forgot how much fun it is.
My former teacher Johnny, a finest Jazz organist and accordionist , told me once that Jazz musicians looked down upon his cousin Dick Contino during his hay day because Contino didn't play the kind of music Jazz musicians played. I can kind of understand how Jazz musicians will get really bored listening to 3 chords in a song, but I agree with you that polkas do animate audiences at least in senior places. Johnny does play polka at requests, and when he plays, he plays more than what he calls vanilla chords. He manages to throw in things like dim7 and chromatic bass lines but always within the confinement of Polka idioms. A truly great musician.
I think the notion that music is a universal language is so wrong. Conversely, music is probably the most culturally conditioned language. A case in point; even in the same culture, different generations play and listen to different kinds of music. Talk about a generation gap! A former professor of mine who was a missionary to Africa once said that the Africans he interacted with thought Western harmony was a very ugly sound! Wow, we can not fathom it, because that's all we know. We must remember, though, they have different tonal scales. A number of parts in the world use quarter tones that we do not have in our scales!!! Isn't it why the Middle Eastern musicians want different kinds of arranger keyboards? My most favorite music is Black gospel music. It has all the great musical elements and the message for me as a Christian. However, that doesn't mean I only play and listen to black gospel music. Also, I do not judge other musical languages based upon black gospel music. In fact, as a classically trained pianist, playing black gospel music is difficult for me. It is a different language! I play it with an "accent" at best.
I've noticed that good accordionists try to avoid playing polkas. Perhaps they are a little too conscious of the "stigma" attached to it. I will say, play it not for yourself but for your audience - just like the black Jazz musicians almost a century ago here is America who played the kind of swing Jazz their white audiences could understand and enjoy - but after they were done, they would gather together themselves at a club founded by black musicians and for black musicians; there they would play and experiment with "wild" jazz that the public were not quite ready (according to the PBS documentary Jazz by Ken Burns)