I can see your point that business is business and if you find candidates willing to accept these T&Cs then that's you done and you have no further involvement in the employment as such.
Having said that, if it was my company being approached by companies clearly involved in social dumping (my personal opinion of course) then I would say thanks for contacting us but we are not interested in doing business with you. Not running a bussines myself, but have several friends that do and they only work with companies that offer their employees industry standard or above T&Cs. They are all very successful in what they do. One of them ran his business with very modest profits for a long time as a result of the higher costs. However, once he had made a name for himself and his company's way of doing business he secured big contracts with some of the worlds biggest companies as a direct result of his "policies"....
I guess what I'm saying is that we always have a choice.
CP