It's relevant to understanding the theory of the case.
The lawsuit accuses Facebook of not seeking to recruit Americans for PERM positions as the law requires:
> In its investigation, the department determined that Facebook’s ineffective recruitment methods dissuaded U.S. workers from applying to its PERM positions. The department concluded that, during the relevant period, Facebook received zero or one U.S. worker applicants for 99.7 percent of its PERM positions, while comparable positions at Facebook that were advertised on its careers website during a similar time period typically attracted 100 or more applicants each. These U.S. workers were denied an opportunity to be considered for the jobs Facebook sought to channel to temporary visa holders, according to the lawsuit.
In practice, what happens is that an H-1B worker is working for Facebook and wants to obtain permanent residency. To do that, Facebook files a PERM labor certification, which requires it to advertise the position to Americans. But Facebook doesn't want to hire someone else to fill that position--it wants the H-1B worker to continue doing the job they're already doing.
If you think of H-1B as being for people who wanted to seek permanent residency all along, this makes little sense. Why require Facebook to advertise a job someone is already doing to other people just to sponsor that person's permanent residency? After all, this person may have been in the U.S. already for years, and is surely counting on being allowed to keep his or her job and stay in the country.
To make sense of this bizarre system, you have to realize that H-1B was not designed for people who intended to immigrate all along. It was designed to satisfy the demand for temporary workers with people who will mostly go home afterwards. The PERM advertising requirement exists to ensure that there really is no American who can do the job instead.
Assuming for the sake of argument that Facebook does face a shortage of skilled engineers, what it faces is a structural shortage. To deal with that structural shortage, it needs immigrants who intend to work in the U.S. permanently. But we don't have a good vehicle for skilled immigrants to say off the bat "I want to come to the U.S. to work, and I intend to stay in the U.S. permanently." H-1B wasn't designed for that. It was designed to fill temporary shortages.
When it comes to "fixing" the H-1B system, you can't overlook the underlying political compromise. Americans don't support creating a permanent flow of skilled immigrants. (At least, not without concessions in other areas, such as curbing illegal immigration.) It seems obvious to "fix" H-1B by just getting rid of things like the PERM advertising requirement. But if you do that, you're subverting the political compromise that led to H-1B in the first place.