young age and lack of experience
I have experienced plenty in the 27 years of my life (I'll be 28 in a few weeks). Anyway, I've experienced enough of life and dated enough women to know that I have more in common with someone of the same culture, faith, customs, traditions, and even mindset. I find that my personality and way of thinking even better matches than a Polish girl than a Mexican girl for example. Furthermore, I wish to raise my children as Polish Catholics and teach them the language, culture, history, etc. - that is much easier to do when your partner is also Polish.
Like Crow said, I'm fine with dating someone outside of my culture and religion too. However, I want to have children someday and want those children to be brought up a certain way and learn about their homeland, their ancestry, etc. That is a consideration I have to make when chosing a wife, as I'm sure the wife too would want her children brought up a certain way, taught certain customs, perhaps learn a 2nd language, etc. There's going to be less disagree on what language to teach the kid, what customs and traditions to celebrate and when, what religion to raise the child if two people are of the same nationality and faith than two totally different nationalities and faiths. It'd even be easier for a Pole and a Serbian to get married since they have similar traditions, similar customs, and a similar faith than say a Pole and a Japanese or Malaysian.
That is why I said: number 1 - Polska dla Polakow... I also stated I don't mind having foreigners come to the country and cited the Vietnamese in Wroclaw as an example. They contribute to the society (many own restaurants), pay taxes, and most of the ones I met even speak Polish. However, even this group married their own kind - the husband and wife would run the restaurant together.
However, having 'refugees' come in, march down the street with Sharia 4 Poland signs, torching tents and shelters provided for them by the government, tax payers, and charities, throwing out clothes and food like the ungrateful refugees in Calais because the thought the charity worker was trying to give them expired food and proceeded to break into their truck and start stealing stuff, vandalizing sings and pushing dumpsters into traffic disrupting people's daily lives, shouting that their God is the greatest, and groping and assaulting our Polish women is something that I will never support and is my number 1 concern for Poland right now since Germany is right next door and all these issues are happening there. Eventually, Germany and Sweden are going to be too full and these 'refugees' may start looking elsewhere. Germany is their first choice because the welfare system is so great that they can live off the government and not work but still have food, housing, and money and spend their days complaining about the German locals - kind of like the welfare, section 8'ers in Chicago complain about how the white man is holding them down even though it's the white man supporting their lazy non-working lifestyle. Eventually, they're going to look at 3rd, 4th, 5th, etc. choices and I'm willing to bet that life in Poland is a lot better than Afghanistan or Iraq for the average person.