That happens when you google idioms in other languages ... you have no clue about the actual usage. And they are usually not one-to-one.

German "das ist mir Wurst" is also a lot weaker than "zero fucks given", at least use something stronger like "das interessiert keinen Arsch" (no asshole cares). Also "zero fucks given" in the sense of "irresponsible, he just does it and doesn't care who gets hurt" doesn't really have an equivalent idiom. Maybe "als druff" (just go full power straight ahead) or something.