The title is a little misleading.

The title of the original post is "Analysis of 2.4M H-1B records shows $50k annual wage gap between employer types". That's not at all what the HN title conveys. The specific wage discrepancy is by "employer type", not some general discrepancy.

The section on geography is better.

The section about specific employers doesn't seem to go anywhere toward an analysis of wage discrepancy. It's just a statement about concentration and a hand-wavy extrapolation to wage discrepancies.