I don't know if I'd call the SLS a terrible idea. It's been a FANTASTIC way to enrich lawmakers, a true masterstroke in pork barrel spending.

And how does that relate to this particular issue? Had they been playing political games for the sake of funding, they would've immediately jumped as soon as Musk and Trump barked, right?

Instead they carefully and patiently explained all the issues, and what is going on.

And yet, still, "ah yes, it's NASA that is lying for political clout, not the very public very shameless very serial liars"

Blaming NASA for SLS is something I keep seeing but isn't it entirely congressional pork barrel politics that makes the SLS what it is? What degree of control does NASA itself have to force a project of that scale not to devolve into such a mess despite congressional corruption?

Exactly. If NASA had full control over how and where SLS money got spent, I can guarantee you the thing would've been a success a decade ago or more, and we'd have American boots on lunar ground full-time by now.

It's a mutual affair. Congress dictates the programs and NASA carries them out with substantial discretion. But I think the thing that really makes NASA deserve the blame is that they cheerlead for it all endlessly, and compel their astronauts to do similarly. More or less literally every single interview NASA carries out or does with their astronauts, they'll make sure SLS/Artemis are brought up, and pretend it's all just amazing.

This results a very misled electorate, which are the exact people that could (at least in theory) put pressure on their representatives in Congress to stop wasting tens of billions of dollars that could have easily had us on the Moon, if not Mars, long ago. But even more in general - people are forced into doing stupid things all the time. That's part of life. But the second that you begin praising those things, you are now a part of the problem.