I have not heard of a specifically Swedish addict gene, and I've lived in Sweden for over 6 years. Searching now, I found no mention of that concept, including searching for "missbrukare gen". Surely some may have said it, but it's not a widely held belief that's part of the debate on substance abuse.
And of course this part of the thread started because you made a statement about puritanical Swedish religious beliefs of the 1800s, when it appears that religious beliefs in Sweden during that time were decidedly anti-pietism/anti-puritanical.
What I conclude from all this is that you feel that your generalizations are correct, even though your details are not, and you make statements without worrying about checking those facts, or feeling that you need to explain the reasoning behind your generalizations.
Perfectly fine for you do to that, but it's not the conversation I wanted, or want, to have.