Similarly to identity-conservatives, for whom belief in global warming is heresy and tax cuts are gospel, I believe there is a similar phenomenon with identity-progressives around immigration, in this case specifically the H-1B program. There seems to be some belief in its sacred power that is not to be questioned and not to be curtailed.
As I see it, big businesses - not least the major tech companies - are loaded with incredibly bright, incredibly well-compensated staff. These companies can figure out solutions to the toughest scientific and technical problems, can create new markets when regulations shift, and change the world. They sure as sh*t will figure out how to adapt if immigration policies change and the H-1B program is reduced. As it stands right now, to me it seems - by and large - a handout for companies to get mid-range IT talent enslaved to them for a fractional price of what they'd pay an American.