His logic is sound.

Rent controls discourage the building of new Rental apartments.

A 5 year window was opened in '92 that allowed  for building completed after '91 to be temporarily excluded - emphasis on temporarily. 

Why would anyone commit to a multiyear project whose viability depends on a temporary exclusion to a bad law, and whose lifespan is at least 5X the life of that temporary exclusion? 
 
The threat to reintroduce rent controls proves that all the people who didn't want to rent out properties because they didn't trust the Government were 100% correct.

Hard to think of a better example of Government making a problem worse.