I'm as American as sweet potato casserole
So you understand the difference when it comes to customers and service , where I live we depend on agro tourism (at least until covid) we have technical colleges with courses dedicated to tourism , I assume they teach people about customer service, but I can't see it filtering down to the shops.
Maybe the problem a cultural thing, but its not something you see in wider Europe, I don't see it as a big deal but I can see how it effects visitors and we can see from this young lady's experience that she has complained about Polish clients within her shop.
But I guess her clients seem not to be professionals more seasonal workers and maybe there lies the difference.
Just debating and putting forward my view of things, I don't think Polish migrants are bad people just they are from a different culture,
dare I say not really customer service focused be they customer or client.
But It could be argued that they are just being honest and don't see any need for false smiles or behaviour when it comes down to doing the shopping or dealing with clients.