No it wasn't ok. They took the money, and then kept it quiet. Everyone in Miami knew they were journalists, they were well known and their participation in Radio Marti was public knowledge. Only the fact that the $ originated in Washington was secret. And this is why their employers sacked them.

Your litmus test is a good one. If you don't mind that the activity is made public, then it is OK. In my case, as long as the article carries my name I am making no effort to disguise the fact that I sold it, or that I sold the rights to someone who resold it. In the former case, I profit from it openly, in the latter, I do not profit at all.