Well the main argument against oil shales is the fumes which come from the processing of oil shales.

But as you say governments are increasingly under fire and Oil Shale Exploration is one of our cost effective solutions. If we were to begin the change to Wind for example the costs on governments (and everyone within the country) would be unbearable bearing in mind the existing inflation and consumers tight pockets as is!

On the other hand I think critics should still voice their concerns as developing an eco conciousness is important.