Trivially non-contradictory. Consider a hypothetical situation in which all the good skilled workers are on visa statuses that do not permit work and have missed the H-1B lottery. Both things are then true.

That would require that there are no local good skilled workers, so the argument they are being replaced doesn't hold.

The comment isn't talking about local workers. It is talking about (a) foreign workers who are skilled, (b) low-wage less-skilled foreign workers and how the H-1B fails to achieve its stated aim in two respects because it's easy for there to be unemployed (a) and employed (b).

The comment contains no argument that local workers are being replaced.

> The comment isn't talking about local workers.

I think you and I are talking about different comments :-)

consider: age discrimination; or an otherwise very talented person is tied to some location (eg. home, or a rural town, due to dependents, or disability), or has the same name as someone "bad" in the news and thus look scary when googled (eg. "I'm John Tillman the nice Portland engineer not John Tillman the NY rapist!" (name is random contrived example)), or once made an un-PC undeletable post in a public forum, or is non-English-speaking, or simply bad with social skills but otherwise great engineer, etc. Also, much of the modern recruiting/hiring culture is still very oriented towards erring on the side of false negative/rejection, and riddled with irrationality and institutionalized jerky behavior.

If an engineer is Famous (due to several public accomplishments), like yourself, you may not have to encounter any of this. "Who cares where he lives or what he's said or how much money he wants, or age... it's Walter Bright!"