Poland, like any other country, do NOT have to issue visas and therefore have the right to refuse visas and do not have to give any explanation.
Indeed. Nor can you take any reason they give you at face value. If you are security risk, they are not going to tell you.
I assume all the Third World people who try to get visas for Poland do not give a sh####t for Poland as they see Poland as a entrance door to EU since obviously they mean to move further west.
Many have legitimate job offers from IT companies operating in Poland, and a few are highly qualified financial specialists. But for the rest, like Sahil, what you say is invariably true. Even the engineers and specialists view Poland as a stepping stone to greener pastures.
If a visa is refused, the applicant has to make other plans to go to another country and that's all.
Trying again and again after being turned down is a senseless waste of money and time.
Perhaps you have ever tried to assist a Non-EU citizen to get a visa and they had it rejected?
I have helped. Many times. Holding them by the hand. To both Poland and the US. The applications to Poland were all turned down, as expected, because of lack of funds and lack of credible ties to their homelands. A small bank account is a red flag that might indicate a high risk of becoming an economic refugee. Not necessarily, of course, and they are aware of shenanigans to manipulate this, but it is still taken into consideration as part of the big picture.
The US visas I helped with were a different story, and were all approved for serious students with serious scholarships. Even then, the most stressful situation I had in my twelve years in Poland was when one of my students was turned down (he had a full-ride athletic scholarship at a good school). Years of my work and his just flushed down the toilet. Fortunately, after a week, the consul called him back to let him know that he had made a mistake and changed his mind, thank God.