Agreed, not much you can do except for trying to educate people and push them in the right direction. No legal recourse can be taken unlike in my scenario (though I don't think many people do get punished for selling fake rolex watches, although it's not something I know too much about!).
Education is the way. A fork is an altcoin, they can try to steal the bitcoin name but they can't because they came later, MUCH later.
You can order clones of almost anything from China, with varying qualities. For a small fee, they can stamp anything as the "brand". If you attempt to resell that in another country where counterfeiting is forbidden, you might get in trouble; for selling in those countries the clients usually just stamp another brand.
This is not related to free open source software of course. Forks are welcome and part of the ecosystem, but its up to you to make your fork "better", and for the people to welcome it. Sometimes forks add ideas that get implemented in the main tree, sometimes they dissolve as nobody wants them. Its part of the freedom of free software.
If you copy Linux, change its name and say its yours, the community will immediately denounce you for plagiarism. The correct etiquette when forking a project, is to give credit where credit is due. Some licenses make this obligatory, and some even require you to publish back your source code.
Calling the forks "Bitcoin" is a blatant lie. They have officially different names, although they use "Bitcoin" as part of their name, they are not.