More digression-
Construction labor-
In Alberta, to work as a carpenter, one must be a certified journeyman, a registered apprentice, or holds a recognized trade certificate. Casual labor can only act as helpers, etc.
The same is true for all other trades.
Apprenticeship for carpenter 4 years on the job training, and 8 weeks of technial training each year.
Is not the same demanded by the licensing boards in the States?

Anyone who builds a house with unskilled or unapproved labor is just stupid; it is doubtful that the house would pass the necessary inspections.

The letters I quoted were by the head of the California Academy of Family Physicians, and a medical student- The NY Times staff did not write them. Rig-'s assertions are nonsense.