Brazil Voids Merck Patent On AIDS Drug

I found this news yesterday. It seems like what they've done is basically take the key to the patent office and just taken what they wanted.(Much like they did in Armageddon, but that's a different story).
Brazil has a lot of people infected with HIV and AIDS, and since this is a terrible disease, I can understand the government's want and need to help their population, but I'm not wild about governments breaking laws whenever it damn well pleases them. In this case it was for a "good cause", but who determines what is a good cause or not. Just because the majority things something doesn't necessarily make it good. (Intelligent design comes to mind)
It's a bit like banning Nazis and racist speech. Sure, most people think it's bad (me included), but where does it end with regards to telling people what they can and can't say and think.
Granted, "borrowing" a patent or two isn't quite the same thing, but doing things like this can set dangerous precedents for future rulers to do what they wish with our rights. Human and corporate-