Is that a fact? "Ignored" by whom, and how exactly?
Applicants must prove they are indeed exceptionally skilled. Sponsoring employers must prove the candidates are skilled. The petitions involve CVs, references from colleagues, diplomas, supporting evidence, interviews, all kinds of proof. Are you saying it's all just bullshit?
Look, we've all met "bad" software engineers. But how much of it is simply subjective judgement? You can't possibly claim those are people coming here on a free pass.
For what it's worth, I've met plenty of mediocre "natives". Maybe it's just the talent pool.