That's why I also said "the way things work here" because it's a cultural thing; you just don't mess with worker's right in Europe. It might not be against the law, but it's not a normal practise. From what I found online last time this happened in Sweden was in 1920s. I'm not from Sweden but I am European and I know that unions and strikes are a normal thing and everybody supports them.
If Elon tries to forcefully break up a strike, he will just amass the wrath of other unions and the entire Swedish population turning an issue of collective agreement into a political problem. I honestly don't see this ending well for Tesla.