I thought the Swedish speaking minority was very small l liberal. Certainly the Swedish Peoples Party quite progressive
There are differences between SPP voters in Southern Finland and in Ostrobothnia. This was apparent in the intra-party discussion on going into coalition with the Finns Party last year: the Ostrobothnians were more willing than the southerners. But in any case, the SPP's purpose is to be primarily a language rights party, and hence a socially conservative Swedish-speaker is still likely to vote for them even if they don't agree on everything.
Of course, Alexander Stubb is himself no conservative. But he did win with the votes of conservatives.
Sounds kinda like how English Quebecers vote en masse for the Quebec Liberal Party no matter where they are on the political spectrum...