You're confounding tyranny of the majority with corruption; the reason marijuana is still criminalized in most places is because a large enough percentage of the population thinks it should be, for whatever reason.
Another example would be the woman who has the gall to braid hair without a license - if she hadn't broken the law, nobody would talk about it, there would never be any chance for reform, and we would all be incrementally poorer for it.
I'm not taking a position on specific laws, just that it's important that some laws occasionally be broken so that as a society we can test whether or not it matters if someone breaks them. If breaking a law doesn't result in negative outcomes, it shouldn't be a law.
The counterpoint is that civil disobedience requires harsh punishment of the disobedience in order to be effective. If somebody flagrantly violates a law because they claim it's bad, and walks away with little to no punishment for doing so, the public's impression will be "well, must not be such a bad law if that's all that happens", which will not serve to change things.