I very much disagree with that assessment: here's why. (2 videos.)
I don’t=it should be but it isn’t
But I don't think apply to the Lerner case. I'm no lawyer, but in a formal (not street) situation, you cannot give testimony and then refuse to be cross-examined.
For example, a defendant at a trial does not have to take the stand.
But if the defendant does take the stand to proclaim his innocence, the prosecution has every right to cross-examine. The defendant has waived his 5th amendment rights in that case.
If I'm wrong, perhaps a FR lawyer will correct me.