You've dodged the question, with respect, as I didn't ask why celebrities with tonnes of cash move around the world. The answer to that is obvious, it's all for tax reasons.
I dont think I have dodged the question: It does not matter if it is celebrities with tonnes of cash who move to other countries, or ordinary people with no cash in search of work to earn money for their familes, in principal it is still the same, they move because it is a financial advantage for them.
If the celebs were not celebs it is most likely they would stay in their own country of birth, and if the Poles that have migrated away from Poland had jobs, or if their jobs were well paid, then most likely they also would have stayed in Poland. (example about 6 years ago lots of British nurses took up jobs in the USA, because the money was much better)
No the ones that remain
Are the Polish that remain in Poland the ones to be proud and the rest have just sold-out
No the ones who you classify as the lot who sold out are still proud of who they are (are you not proud of your parents ) and where they were born, but remember a large majority who left did not leave with the thought that they will never return.
The British nurses who left UK to take up better paid jobs no doubt are very proud to be British.