Sweden is not anti-theist; most here are so non-religious that they don't even bother calling themselves "atheists", as it doesn't matter one way or the other to them. They're as much anti-theists as they are anti-Fenris-wolf.
More violent than what? Syria? Afghanistan? Daesh? They are certainly not anti-theist.
If we're not the great nation we were, it's because the right-wing government that ruled between 2006 and 2014 "sold" our collective assets to their billionaire friends for peanuts. So, less tax-income to the state and more need to use private (i.e. more expensive) alternatives for us taxpaying citizens.
The most violent ones are young men within right-wing Nationalism. As they are traditionalists, they probably want the State Church back.