They have a point...to a point.
A good argument could be made that those practicing medicine or law or whatnot should demonstrate certain skill levels because the harm they might inflict through bad practices could be irreparable.
But OTOH when you have to be licensed to give guided tours in Washington DC--where there is no conceivable scenario of serious harm through malpractice--then things have gone too far.
It ain't just the Feds, either. The states pile their shit on top of the Federal rules.
Alas, that is their perogative if the 10th A is to mean anything. It is their economy to kill.