Between 80 and 90% of those eligible to vote (all 18yrs or older) in
Sweden participate in the elections, and it's been like that since after WWII. Similar stats are common in Europe, so I guess that's not what the author is refering to.
But do the voters do anything but get bribed into slavery?
There is no real free-market party or constituency in Sweden. Neither the Moderates nor the Christian Democrats (which my grandparents always vote for) want to end the welfare state. At most they want to make it more efficient and not add new programs.