You do not know enough about immigration and are spewing falsehoods.
First, a visa is not permission to stay in the U.S. A foreigner can have an expired visa and a valid status to be in the U.S. (they can take their time at their leisure to apply for one). Conversely they can have an unexpired visa but no permission to be in the U.S. (such as when they have a H-1B visa but is actually unemployed for a long time).
Second, this entire process of advertising fake job openings is not at all related to visas, H-1B or not. It's related to the employment based green card process. Hiring an H-1B requires a Labor Condition Application from Department of Labor, not a Permanent Labor Certification. The former does not require any attempt to hire American workers.
Third, even if some Americans apply for these fake job openings, that doesn't mean that foreigner must leave. After all, the foreigner still has valid H-1B status (see first point). It's a setback to their green card process only.
Fourth, whether or not the job can be filled by a local is determined by the company. Sure such determination will need to be submitted to the government for approval. Imagine that the company requires 10 years of experience with Ruby but the local has 9 years of experience. Guess whether the company will see this local as qualified? There's no good way to solve this problem. Companies can require whatever skill and experience they want in their job requirements. The government doesn't determine whether the job requirement itself is sensible. It just checks that no locals satisfy the job requirement. Do you get the point now? Companies can construct the job requirement however they want such that the job cannot be filled by a local. Companies are not abusing any law. Companies are exercising their right to choose qualifications for the jobs.
Fifth, you say "sucks for the unemployed locals" but there is no requirement for companies to check that the local applying is currently unemployed. This is not a joblessness reduction program. Maybe the locals who are applying are just switching jobs, in which case if they succeed their old employer loses a headcount. There's no net change in employment figures. The law doesn't care.
Next time before you spew falsehoods on HN, spend an afternoon learning about H-1B, LCA, PERM, EB-1, EB-2 and such topics. Before you accuse companies of committing fraud, consider whether the law actually allows what the companies are doing and whether it is the law that should be changed. Considering directing your anger from prior administrations to Congress instead.