Much of it goes to enrich contractors. Lockheed Martin as a usual suspect here, for example.

Building a rocket that is hard to launch and costs a fortune is a boondoggle. Talented scientists and engineers can waste their time building the wrong thing.

What other current rocket system matches the specs of the SLS, or has the same goals? The only thing comparable is Starship, which isn't ready yet.

There are legitimate complaints to be made about things like cost plus accounting, but the project itself isn't a boondoggle. Like, the people who greenlit it aren't idiots.

If you want to complain about boondoggles, look at the military.

If all talented scientists and engineers do is work on boondoggles, maybe it is not so vital to pay them?

Who is the boondoggle decider?

I'm just saying, you can't say "It's not a boondoggle because a lot of talented engineers got paid!" That's not, a priori, a good thing.