Have you seen the price of deodrant in Poland? For most relatively ok brands it costs the equivalent of three hours pay.
You can get a good antiperspirant for about 12-15 zł. That's an equivalent of about 4 bottles of beer, 2-3 packs of cigarettes, 8 - 10 loaves of bread. And, mind you, you don't use all at once. Most people can afford spending 12 zł per month for an antiperspirant.
It's the custom in some countries to have a Saturday night bath and that's it for the week.
Unfortunately, some groups of Polish people have the same custom (mainly old, uneducated and poor). I've even heard that a real man bathes only once a week.
OK, I will try to answer the question. I use public transport almost every day and very often I have to stand next to someone who stinks like hell. And sometimes I'm really frustrated. It's true, that a lot of people in Poland stink.
People in Poland have very different hygienic habits. Apart from people who wash at least every day, change their clothes frequently enough and use antiperspirants, there are those who treat hygiene like peasants did in 19th century. E.g. for many people a deodorant is not something to keep you from sweating, but a thingy that women use to smell nice when they can't afford perfume. There's a lot of men in Poland who never use deodorant and don't even think it's something to do with hygiene. They also wash too rarely and wear one shirt for a week. Women are usually more careful about their hygiene even
the ones from the same social backgrounds. The biggest problem is with old people - their natural B.O. is worse than young people's, so they should be even more careful about hygiene. But, very often, they aren't careful about hygiene at all. Their senses are numbed, they can't feel they stink, so they think everything is OK and they don't wash themselves. No, they don't think one should wash BEFORE one starts to stink. I used to have a neighbour - an old lady - who smelt really bad. Her flat smelt, too. When she opened her door, the whole staircase stank unbearably. I could smell it long after she shut her door.
When you get on a bus, it's very probable, that you'll come across one of the stinking ones.
So the answer is: it's not about hard work, poverty genetics or anything. It's about bad habits still cultivated in some social backgrounds.
And to non-Polish people surprised reading this: I know you might been to Poland and have met only nice, civilized Poles who have nothing to do with such barbarians. But remember - when you go to Poland you only talk to people from certain social backgrounds. You usually meet those nice, civilized, tolerant, European, polite Poles. But you can't judge the whole society basing on them. You usually only get to know people who speak some English - i.e. the better-educated part of the society. But those people who carry that Saturday night bath custom usually don't speak any foreign languages or even proper Polish.