They are volunteer opportunities, typically sought by folks who don't need an income (retirees, students, etc). If you're looking for paid work, there are alternatives:
The map data entry opportunity that seems to be available in every state was closer to what I expected, some projects people could spend a few hours a week on in their hometown.
But in general, I agree with you. From what I can tell, even though this is just broadly called "volunteer.gov", it really seems like it's specific to the Bureau of Land Management/National Park Service, and is missing a large amount of types of positions that I think most people would expect when they think "go volunteer".
This isn't a bad thing, just isn't what I expected when I saw this post.