Of course you sign a contract when doing business. It's like that in any market economy.
What's peculiar about Sweden is how that extends to the labor market. So instead of commercial civil law you have contract law. That's the only difference.
Tesla can either negotiate a contract and do business, or exit the market. They are free to do either.
What seemingly confuses people is that Tesla is not breaking any civil law. Only contract law, which the market has organized around, and which it is free to refuse their business about.
They have options of course:
1) Stop doing business in Sweden.
2) Sign a collective labor agreement that ensure worker's rights just as every other company that operates in Sweden.
Complying with labor protections is not extortion.
And if Tesla does not wish to comply with the norms in Sweden they definitely should stop operating in the country.
This is buying a ticket to the movie and then a mobster taking another fee at the door.