....should....know....the....basics....
Absolutely. But for someone who doesn't and can't understand why setting the state on an input port pin makes no sense, it ain't gonna happen.
Swordfish does insulate the user from a lot of the details. I know many people here who would say you have to know every page of the data sheet, that you must learn programming starting with assembler and it's supposed to be a long painful process, but it doesn't have to be. For routine stuff, if you pick the right include modules in Swordfish, you don't need to know the nitty gritty details. It will help if you do, but it's not essential.
If you're trying to use special features of the micro or do something unusual, then you may need to break out the data sheet, understand the functions of all the resisters and so on.