The major issue with the H-1B isn't the Indian consultancies, who contribute to some of the more egregious abuses, but the regular tech companies: The Intels, Microsofts, IBMs, EMCs, Googles, Facebooks, Amazons, etc. It's not that they are replacing employees that are citizens it's that they are preferring the H-1B and OPT for open positions.

Modern tech corporations have been automated to the point that the biggest cost is labor, so they are now spending a lot of effort to address this cost. The claim that there is a STEM shortage is a myth invented by these corporations in order to lobby and expand these programs. They operate within the letter of the law but not in the spirit, with misleading job advertisements and preferential hiring practices. This becomes a self fullfilling prophecy in that the smart people who are paying attention are driven away from technology.