I agree. I have a hard time believing they would now think enclosing crawl spaces would be healthy for a home. As a former appraiser I had the pleasure of being required to inspect the crawl space of every home. If I remember correctly, the three things I looked for were:
1) a minimum height
2) vapor barrier
3) proper ventilation

In fact, if the crawl space vents were covered up with styrofoam or cardboard, I made the owners remove them. IMO you want/need adequate ventilation in your crawl space. You want it to be cold and drafty down there, not warm and moist. Warm, stagnant, moist areas encourage mold, dry rot, and pest/rodent infestation. Moisture ants, rats, mice, (and larger critters) all love a nice warm dry place to inhabit for the winter.

Ike