I'll admit, as an attorney, this isn't my specialty, and every jurisdiction varies, but the ye olde common law of tortuous interference requires something more than mere competition, this is America, not the EU.

2 DAN B. DOBBS, THE LAW OF TORTS §§ 448-52 (2001)("you are thus free to induce my customers, employees, or suppliers to deal with you instead of me, as long [as] they are not bound to me by contract").

Restatement (Second) of Torts § 768 (1979) (stating that interference with a competitor’s contractual relations is permissible if it does not employ wrongful means and is intended to advance the competing interest).

Wal-Mart Stores, Inc. v. Sturges, 52 S.W.3d 711, 726 (Tex. 2001) (" we conclude that to establish liability for interference with a prospective contractual or business relation the plaintiff must prove that it was harmed by the defendant's conduct that was either independently tortious or unlawful. By "independently tortious" we mean conduct that would violate some other recognized tort duty.").

Correct, tortious interference has criteria, and making competing employment offers doesn’t necessarily or automatically meet those criteria, but it could if there are other factors involved. Again, it depends on the situation.

You’ve asked two different questions. One about legality and the other about public perception. There are lots of things that are legal and still considered unethical. And there are lots of things that might or might not be legal, that businesses avoid simply because there’s legal risk, and/or avoid because there’s risk of negative perception.

If everyone involved in a startup agreed to be individually hired, and divest interest in the startup, and there was mutual understanding on all sides, then there may be reasonable chances of success and no lawsuits. I think that probably has happened before. If not everyone agreed to it, and a company tried to acquihire all the individuals of a company forcefully without agreement by the investors and founders, there’s a high likelihood (risk) of legal conflict, and the likelihood will increase under US law if the acquiring company would start to look anything like a monopoly on the market in question after the unofficial “merger”, right?