I am Finnish and as such I get his management by perkele-reference very well and should probably understand what he means by claiming his rages on the KML are somehow particularly Finnish if communication is culture-dependent ;-)
We do tend to value being to the point and no-nonsense, but I can't really see being too much of a raging hothead as being a very Finnish feature -- it would detract from actually getting stuff done, and you'd lose face by losing your cool. Mgmt by perkele is actually something Finnish corporate types are trying to get rid of and it hasn't been done since the 80s, as too authoritarian military-style structures do not serve a modern organization well.
As a funny cultural anecdote, I find it interesting that Linus would identify with cursing and these things. He is a Fenno-Swede after all, and their minority culture tends to stress to the point of hilarity their relative high level of civilized conduct as compared to us barbaric Finnish-speaking forest people... if the TV shows that push the "correct" view of our Swedish speakers are any guide, he should be exchanging pleasantries with his boyfriend on a boat in the archipelago while knitting Moomins and sipping champagne.