Maybe Sweden is (rightly) worried that the Russians would like to get their Eastern European empire back, and that warfare might spill over onto Swedish territory.
BTW, I heard that one way the Swedes kept Nazi Germany from thinking of invading was by letting it be known that they would blow up the Swedish iron mines in the event of an invasion. Germany needed the iron trade with Sweden for its war effort.
Yes, I think the definitions and examples you give are correct. I would add that populism can be either right or wrong, at least in its inception, depending on how corrupt the establishment being revolted against may be.
If the populist movement succeeds in throwing out the scoundrels, and replaces the scoundrels with decent, reasonable people, then fine. Unfortunately, it has often historically been the case that even bigger scoundrels move in to fill the political power vacuum.
And of course, the Evergreen insurrection was populism of a perverse, unreasonable kind.
And as for Rompuy, he would do well the ponder the policies that brought on the populism he fears. Some of that populism is indeed unreasonable, but some is not.