Are you guys sure it's only baseless whining?
Yes. If you look at the - for instance - gazeta.pl forums, you'll find that emigrants have a habit of painting Poland as some sort of terrible place.
Also, why would the Polish government be concerned of people with poor education leaving the country
I'm not actually convinced that the Polish Government is that bothered by it. Most of the people leaving are unemployable anyway for various reasons, and the phenomenon is similar to the Yugoslav emigration of the 1960's and 1970's to Germany.
but there must be at least some truth to them if the number of emigrants is on the rise again.
What *is* true in the comments is that there is little future for badly educated people living in villages, or for people who studied crap degrees without having any sort of connections. But the first point is true everywhere, and the second point is directly related to the Polish work culture, or lack of. Most students are horrified at the thought of actually gaining work experience in their holidays, which is again the norm in some Western countries.
I can speak from first hand experience - it is nearly impossible to find students willing to work on projects for their own self development within Poland. They simply don't want to do it if it clashes with things like going home for the various long weekends, summer holidays, etc etc.