The tract builders already bought and developed the land (e.g. ~100 parceled lots) before COVID but the individual lots were unsold. The "housing starts" statistics are official US Department of Commerce data instead self-reported numbers by homebuilders so it's very possible that there was a real uptick in selling off those unsold lots that were previously moving slowly.
E.g. See satellite photo of two neighborhoods in suburbia under development by a tract builder like Toll Brothers:
https://www.google.com/maps/search/toll+brothers+neighborhoo...
... and the street view shows the showcase model home and the construction equipment already building on those lots:
https://www.google.com/maps/@41.0783819,-74.1180052,3a,75y,1...
Multiply that type of scenario happening all over the country and getting accelerated by coranavirus fears. A builder can get heavy equipment out on the empty lot within a few weeks after a new house contract is signed.
I do agree that skepticism is warranted. We should be seeing parallel stories of falling prices of city apartments and condos.