"Europe" does not have a unified stance on this, don't paint our entire continent as The Borg.
If you are Dutch, just take a one-hour flight to Copenhagen to see how a city can be absolutely plastered with national flags.
If Poland or France were introducing a new nationally produced rocket, they would certainly show their national flags around it as well. They definitely do so when displaying new weapons. So does Ukraine etc.
Accidentally, I remember the Dutch colors on every package of Dutch cheese I ever bought.