Translation:No, one is not allowed to get married to two people at the same time.
To be honest, I can't remember exactly what I was thinking, as my comment is over four years old. But I would assume the question was about whether this meant being married to two people, or getting married to two people, with polygamy meaning the former. Of course, I agree with everything you said as well.
No, it's not silly .. it happens whether you like it or not, even with the willing consent of all parties .. I'm pretty sure there are polyamorous couples, probably also in Sweden, who want to get married legally in one ceremony.
Polygamy has been banned from western culture for good reasons, but on the other hand it restricts freedom, which restricts thinking, which is perfectly natural, so I won't call that silly.