First of all, ignore the racists. Many of the racists on this board have never even been to Poland. I lived there for twelve years, and I have to say that Poland is not an especially racist country, at least as far as overt racism goes. There is a subtle form of racism, though, that you will meet with, which I will describe later.
Second of all, your logic about the 36,000 students is a bit faulty. By far the bulk of them are Polish, and they are studying there not because the school is good by global standards, but because it is the best they can get being Poles. They will be studying in Polish, whereas you will be studying in English. There is a huge difference.
Polish universities have started teaching courses for foreign students in English, and have been rather aggressively recruiting students from poorer countries in Asia and Africa. Sadly, their advertising has been less than honest. They, together with unscrupulous "recruiters", "consultants", and "agents" from these countries themselves, have been telling prospective students a whole host of blatant lies about the quality of the education, student life, the worth of the degree and, worst of all, the possibility of finding part-time jobs in Poland during studies and the possibility of finding work in Poland or richer countries after the studies.
The truth is that an engineering degree in Poland is no better and opens no more doors than a degree from a good university in India. The quality of education is inferior to that in the richer countries of western Europe or the English speaking countries, primarily because there is not very much R&D money available in Poland, especially in a field like aerospace engineering.
Courses taught in English for foreign students are sort of a scam. The school is doing it to earn money off of gullible and desperate Asians and Africans. The quality of courses taught in English is generally much lower than that of courses taught in Polish, and even the quality of courses taught in Polish is much lower than that of universities in the US, the UK, Switzerland or Germany.
The main problems with technical education in Poland are:
1) A lack of practical courses and hands-on experience. Education tends to be very theoretical. Laboratory equipment is outdated and scarce. Laboratory courses often consist of demonstrations by the teacher rather than hands-on work by the students.
2) There is very little R&D money in Poland, The rather small US state of Connecticut, for example, has much more R&D money flowing through it than the entire country of Poland. For an engineering student, R&D money is like blood is for the body. R&D money funds interesting and innovative student projects, internships and jobs, and makes well equipped labs possible. As an aerospace student, you should be looking into universities that receive a lot of aerospace R&D money. There aren't any in Poland, including WUT.
3) Polish universities are lousy at building and maintaining relationships with local and global business and industry. This means it is harder for Polish students to network and find internships and jobs at home and abroad. It will be much, much harder for you as a foreign student.
4) A degree from a Polish university is no better on the global market than a degree from India. Why go through the trouble and expense of getting a degree from Poland when you can get the same thing from a good university at home.
5) The drop-out rate from Polish universities is staggeringly high. Out of 100 students that start studies, less than half finish. For foreign students, even less go on to graduate. Polish universities provide very little support for students, and even less for foreign students. Compare that to the US, for example, where by far the majority of incoming students will eventually graduate, and universities practically dance around students. One of my Polish students is now studying engineering in the US, and the amount of support he gets from the university is light years ahead of anything you will find in Poland.
6) There is little financial aid available for Polish students, and essentially none at all for foreign students. There are few part-time jobs for Polish students, and essentially none at all for foreign students. If you cannot afford to pay for 100% of the costs of your studies and stay in Poland, then forget about coming to Poland. You will not be able to finish your studies if money runs out, and you will have great trouble getting the work you will have done recognized by a university in another country.
7) Internships, even in technical fields, are usually unpaid. Even so, it is incredibly difficult for foreign students to find any internships at all.
Sorry, but I really can't see any reason why a foreign student should study in Poland. Yes, it may be cheaper in the short run, but the long-term return on investment is much, much lower than studying in a richer country in western Europe or the English speaking countries, or Korea or Singapore. It's no better than studying in India, for example.
Don't believe "consultants", "recruiters", "agents" or internet sites like "Study in Poland". They are lying to get your money and don't care whether you will be able to finish your studies. Like I said, it is a big scam, and, frankly, it makes me want to puke.
Now about racism. You are unlikely to encounter overt racism as a student in Poland. However, you will encounter a more subtle form of racism that I call "benign neglect". Basically, people will just ignore you. You won't be excluded, exactly, but you won't be included, unless you are a very assertive, self-starting person who actively goes out and persistently seeks friendships. If you are shy and reserved, it will be as if you are invisible. Poland is a rather closed society, and breaking into it requires quite a bit of work and ingenuity for a foreigner, especially one from Asia or Africa. Otherwise, you could end up being very isolated.
Also, the language of the country is Polish. It's a difficult language that you will almost certainly not be able to learn well enough to fit into society. It takes many years of very hard work, and you will definitely not be motivated to learn it, based on your comment about "opening doors" in your post, as learning Polish doesn't open any doors outside of Poland. You won't have the time, either, as an engineering student, to learn more than a few phrases at most.
Hope this all helps.