He may have conflicts of interest.  That does not mean he is wrong, or right for that matter.  Limitation of supply probably does have an impact on prices, but if demand is soaring and apparently unlimited, supply won't matter.  You can try putting out a fire with gasoline but you need an awful lot to make that work.  Usually you just get a bigger fire.  I have had real-estate friends complaining about lack of supply (as if selling multiple houses every month was a right they enjoyed and the demand was natural).  Houses are primarily for living in, not a speculative investment.  You can choose to speculate, but when that drives prices so high that the primary purpose is threatened, then some regulation of the market is needed to preserve that purpose.  We are actually doing the speculators a favor in the end - the prices will eventually crater if we do nothing and, like a pyramid scheme, the last ones in get creamed financially.  Better to cool it off this way.