It isn't about poaching. It is about how vigorously you'd be protecting the interests of your company A in a deal with company B when simultaneously negotiating your personal offer with the company B, especially if it is [even if just implicitly] packaged together i.e. "the offer happens only if the deal happens." You don't see a conflict of interests here?

There is no evidence that any of these companies had contracts with the acquiring companies before reaching out to the employees.