You don’t “get it”. What I’m saying is that there should be equal pay for equal skills and equal work.
If, as stated earlier there are such rules, then they should be enforced, not allowing greedy Employers to underpay somebody because of the nationality, ethnicity or gender.
If there are not enough nationals with the right skills to fill the available jobs it make sense to import foreigner on temporary work permit to fill the positions and allow the business to thrive, thus bringing in tax $$ and jobs for for nationals in other positions, both higher and lower.
If a person on such visa proves not to be suitable, he/she can be kicked out w/o much ado.
If, however, the person should prove to be a valuable asset for the country and are willing to take up permanent residence, or eventually citizenship, that is a positive, not a negative.