What Sweden did to Finland for most of its history was extremely cruel and it went from bad to extremely cruel during the 17th century in the beginning of the Swedish Empire, which not surprisingly preceeded the rise of Britain's empire. I think Sweden owes an apology to Finland for what they did.
Swedish is an accepted language in Finland, but Finnish is the official language, and is spoken by over 80 percent of the populace.
There is no fact to the claim the Swedes were cruel in the 17th century.
Any cruelty was during the 16th century, during the Livonian war.
The 17th century was predominately Finland's era of suffering under the aggression of Russia.
In 1630, the Swedish (and Finnish) armies marched into Central Europe to fight the Thirty Years War as allies. Why would they ally if Sweden was so brutal?
Sweden promoted what would now be dubbed capitalism. They wanted a strong economic free market for both Sweden and Finland, a region which produced massive amounts of tar for ship building.
At the turn of the 18th century, famine tore Finland apart.
Then the Great Northern War against Russia began and the wars between Sweden and Russia lasted an entire Century (off and on).
This ultimately led to the Russian occupation of Finland.
Russia was far more brutal to the Finns than Sweden.