I think you're dangerously conflating opium and poppy just like people sometimes conflate cannabis and hemp.
I can't speak for all of Europe but here's how it works in Germany: Poppies aren't banned, poppies that can be used to produce opioids ("opium poppies") are. Likewise hemp isn't banned in most of Europe, hemp that has a high THC content is. Actually hemp is more strictly controlled (e.g. you need a license to grow hemp at all and high THC hemp is banned outright) whereas you'll find poppies grow by the wayside or sold at florists - unthinkable for hemp. In Germany (like Poland) poppy seeds are also a staple for bread and sweet pastries, so you'll find them in the baking section of most supermarkets (tho they're likely no good for growing).
Also a fun fact: poppy seeds can set off drug tests so if you know you are going to take one, it's recommended you don't eat anything with poppy seeds in it and if you did, you're supposed to inform the person performing the test because it will skew the results. There are trace amounts of opium in regular poppies even though it's not enough to use them to produce actual opium.
Anecdotally, my grandmother told me that when she was a child it was considered normal to douse a knotted rag in hard liquor and let fussy babies suckle on that.