Living in Sweden, sure, I don't follow mainstream media very closely, but still this is the first time I read these news.

I guess "we" don't want to publish a report pointing to someone "we" see as allied/friendly/good. Despite it being pretty obvious - Russia wouldn't sabotage their own pipeline, not their allies either, and those are pretty much the ones considered bad here, so who is left but the allied/friendly/good? It wouldn't surprise me if threats and/or bribes are involved too. ("we" of course meaning the politician/media/etc. people, not Swedes in general.)