Almost not allowed in Sweden without my Polish passport.

So last August I was in Sweden and I almost wasn't allowed in.... I had just gone to 13 other countries in the weeks prior and 20 countries just last year and yet they kept asking me for my polish passport. I'm a dual citizen with the U.S. I don't have a polish passport. I had an appointment to get one but now with covid it got cancelled to renew it. I have to drive 9 hours to go to the closest polish embassy. But how come Sweden wouldn't stop asking me for it. I had my U.S passport but the guy wouldn't stop saying I was born in Poland and I needed my polish passport. I just kept saying sorry I don't have one. Is this normal? Like i said in the past year ive been to over 20 countries and have never had a problem. Will I need to travel with both passports from now on once I get it? Has anyone had this problem before?

It's not quite normal. Dual citizens can carry whichever passport they want. However, IF they know you (can they know it somehow?) that you had entered Poland on your Polish passport, they may require to enter the bordering country on the same passport. Today's system may be interconnected and they may know more than you want them to ;|