Sometimes you find that nobody else on the Internet has done something yet and it's such a useful building block that you're compelled to make it happen. If you care about the size of government (generally on the right) or how government is used to favor the 1% (generally on the left) both projects are hopeless gum flapping without a list of governments. With a list of governments you can work up to do lists, progress items, measure progress, identify backsliding and counter attacks from the other side. It's such a useful thing for anyone wanting to do any sort of oversight.
In the US, the lowest level of sovereign capable of making new governments is the state. Each state has its own ideas about how to set up these local governments so it's natural that this task is broken down to individual state lists.
In comments, I would like any visitor that knows where such a list is kept to drop a link to it.