It's because it's not about the opinion of voters, but about existing political powers that want to retain their power.

No matter what you (as population) say it will get implemented. If you don't, then they will put sanctions on Poland, withdraw financial partnerships, etc. Like with migrants, they are going to be sent there, even if Polish people vote against.

No matter if you are in favor or against, raising the topic will just make you socially be isolated or even legally punished in some places.

Sad for democracy and free speech.

EDIT: clarified about migrant policy and the decision of countries to choose or not