IANAL either but the images from the Hubble have “artistic” work that goes into them just like a landscape photograph does.

Choices like the the framing, color saturation levels, etc.

Are they actually copyrightable? STScI is of course free to assert that they are, but that doesn't make it so.

How does that make sense for a taxpayer-funded resource? I'm sure that some projects that rent time on Hubble have private funding, but does that apply to all of them?

That images taken by hubble aren't used commercially without paying a license fee to NASA? I imagine the tax payer is okay with getting some money back.

NASA stuff isn’t copyrighted, and only the logo is even trademarked.

> NASA content - images, audio, video, and computer files used in the rendition of 3-dimensional models, such as texture maps and polygon data in any format - generally are not copyrighted.

(https://www.nasa.gov/multimedia/guidelines/index.html)

I believe the reasoning is that everything paid for by your tax money should be free for everyone. I think some state-level governments prefer your argument.