It's quite understandable, imho. Immigration is being allowed precisely for cheap labor, especially when citizens are not prepared to go through the extra hardship - for example, I remember reading that the fatalities when the bridge fell in Baltimore around 1 am, were all immigrants, all on duty at that hour.

For specialized labor, there is always a question of possible espionage and back-channel tech transfer. This is not so much perhaps for India as opposed to other technological rivals, but it may be one of the considerations in the immigration policy being counterintuitive.