Sorry. You are wrong. Yes, technically it is illegal. But it is as enforced as the speed limit. Which means, not. There are several legal ways around it, but the main thing is that there is no enforcement. Or more accurately, very little enforcement. See, no one is documenting the information described in the law. No one is checking up on the corporations. So yeah, the law exists. So what. The corporation is under no obligation to sort their data regarding employment into those nice categories enabling comparisons. So they don't. And no one checks up.
Just because a law is on the books does not mean it is enforced.
The LAC that the poster you rebut noted are bang on. A company is required to follow all these restrictions. We have a LAC file filled with all of these, and they must be constantly updated. I will grant you, that the INS, even when an audit is requested by the employer, don't show up very often, but you must comply, regardless.
FYI, this engineer is the lowest paid in our cadre of engineers, but it is the prevailing wage.