Ask HN: Argument for H1-B

I know the argument against H-1B is that it results in Americans being fired, and Foreign Engineers being hired at a much lower rate than the American who was just displaced. Many Reply to this saying that it is about the skills gap and not about wages. Is there more to the argument for H-1B that I am missing? It's terribly tempting to say it's all about spending less on labour and the skills don't matter. But maybe I'm wrong.