If they had wage parity there is zero disadvantage to a US citizen. The problem is not H1B's as a concept, it's making foreign workers indentured servants paid a fraction of the wage, thus incentivizing their hiring over US citizens.
Immigrants contribute to both supply and demand. It's not at all obvious whether this is net good or bad for natives' pay.
The job should go to the most qualified person. That's how america works. If that most qualified person is actually a guy who was born in india, great. I have no problem with that. You don't get to bogart opportunity based one what zip code you were born in.