Yeah - I know in US law some terms are simply unenforceable and void. Much of the FOSS movement is designed around US contract law. There are issues with some US licenses being enforceable under other legal regimes - I was chatting a decade or so ago with a Russian who understood the...GPL(? I don't remember exactly) to be invalid in Russia and so it had to be bundled in some fashion to be usable.

Or to put another way, a license (a contract) is a tuple (terms, jurisdiction), and the juridical evaluation process will take both into account.