And that's fair. The employee should be able to seek employment anywhere of their choosing. What is being discussed is not the same situation that went on with the major tech firms. In that situation we found out that the tech firms wouldn't hire each others employees regardless of situation.
In a hypothetical situation where you have two companies, lets call them Company A and Company B, who are in talks for an acquisition. If Company A is huge and is potentially an acquirer then Company B would be it's acquisition target. Company A is going to learn a lot about Company B to consider purchasing them. Company A could walk away at any time with all the salary information of Company B's employees.
Company B should have the right for protection in such a high risk situation. A non-solicit agreement that covers employees would prevent Company A from approaching, with the intention of hiring, Company B employees for a period of time that both firms agree upon.
Employees of Company B are more than welcome to approach Company A about jobs. Company B employees may even get a raise since Company A would know how much they are earning. However, Company A would want documented proof to show that the employee of Company B came to them. As they cannot approach the employees of Company B during the previously agreed upon period.
The system needs to protect employers like it protects employees. Not everyone runs a high margin billion dollar company.