What does that say about the competitiveness of the Swedish market for that word, as I doubt they have translated the site.
I would hazard a guess that you don't use the word gambling too much
For what its worth, I think Gambling.com has suffered from a bit of an identity crisis for a while now. It appears to be heavily focused on sport (for traffic I presume), but I don't know too many people that associate gambling with sports betting. Surely the focus has to be casino for them.
Good luck to the buyer, a great domain, but making a return on your investment will not be easy.