I don't think Sweden is significantly more transhumanist than several other western European countries. The fact that two influential transhumanists (Bostrom and Sandberg) are Swedish could be due to chance. Once they became known, they may have attracted a disproportionate number of Swedes to adopt similar views, but that number is still trivial compared to the population as a whole. In fact, it could be that the general egalitarian sentiment makes Swedes less likely to accept certain transhumanist positions (even though that sentiment is arguably weaker today than it was a few decades ago).