Hundreds? Try thousands. You think Rome, Egypt or the Empire of China wasn't full of corrupt bureaucrats? It's part of human nature and is in no danger of going away anytime soon. Oh and disregarding worker safety in the name of profit happens all the time all over the world. Hell, in just the last few days 35 South African miners got gunned down while on strike!
I know it happens, but I was comparing it more to the USA's current situation. I assume when Earth goes into space and becomes some kind of power that whatever government is formed will be run a bit better than the current (2012)governments of countries like South Africa, China, Egypt, etc, and be more like the USA, UK, or other modern democracies, where it has problems but doesn't treat its people like they have no rights. The fact that its atleast some kind of democracy (and I'm assuming its one global government, although they really haven't said) is what gives me that assumption. I know there will be corruption, but what was happening with the dock workers was just bad (and, it turns out public opinion did make the Senate accept Sinclair's position, so it is similar to what we have today). I guess I just assumed it would be a little better, not a bit worse than what we have now.
Like I said, it's neither. This is how it's always been (more or less) and it ain't about to change without something *drastic* to alter the basic psyche of the whole species. Oh and if you think democracy is a good way to protect against corruption, think again!
As for how the Earth Alliance works, it's a "Multi-Tiered Democratic Republic." And what that means is that sovereign states still exist, though a number of them appear to have coalesced into larger super states (Russian Consortium, North American State, United Islamic Nations, Central African Bloc etc.) and most (but not all) of them are members of the Earth Alliance. Each member state is basically free to run their countries how they see fit (though one assumes certain conventions must be adhered to.) Being part of the Alliance means that all members contribute funds to support Earthgov and by extension, the Earthforce military which is responsible for planetary security and overseeing the colonies. In return each nation gets a seat in the Earth Senate, all of which are based at a huge facility besides Lake Geneva in Switzerland imaginatively called Earthdome.
There are still wars between the nation states and while it's never explored in any detail mention is made of the "Liberation of the African Bloc" and a civil conflict within the Eastern Bloc called the War of the Shining Star. Both of which took place a number of decades before when B5 is set, but also well after the founding of the Earth Alliance and first contact with the Centauri.
It's also worth mentioning that the mega-corporations have very close ties within EarthGov and even Earthforce and in some ways have more power than a lot of the Earth nation states. Indeed, some Earth colonies are basically owned by one megacorp or another. You'll hear about a few of them at some point down the line.