These all appear to be full-time unpaid work? Like the expectations are incredibly joblike and the pay is free housing and a visitor's pass to all national parks.
Volunteers are expected to contribute a minimum of three 8-hour shifts per week (8:45AM-5:15PM) with a half hour lunch for a period of three to four months.
Weekend availability is required.
Consecutive days off are offered, except in unusual circumstances.
"Consecutive days off" is much different than "days off"
There's also apparently a volunteer -> actual employment process for national park service.
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.