In this case, they were filling positions through a staffing agency, which (in some cases, at least) can mean that the staffing agency was 'hiring' them and then contracting them to Jabil.

In that case, it would mean that Jabil had no knowledge of, nor reason to have knowledge of, their immigration status. They paid the staffing agency to supply X workers, X workers showed up to do the work, and they assumed that the agency did their due diligence (i.e. followed the law).

This leads Jabil to discover two things:

1. Their staffing agency was breaking the law on a large scale 2. There aren't enough people in the area to actually fill available jobs

In this circumstance (assuming I'm right about contracting out to the staffing agency), Jabil didn't do anything wrong and now they're up the creek, metaphorically speaking.

If your competitors are doing and you were either forced to follow or go out of business… they can have my sympathies.