I'm only talking about the subclass of foreign workers who are educated in the US and already in the country. They surely would not accept longer working hours

I'm only talking about the subclass of foreign workers who are educated in the US and already in the country. They surely would not accept longer working hours or less pay. I didn't say these graduates aren't competing, merely that in the case above nobody is being replaced (in a literal sense) as these were new positions to be filled. Also, they were not filled under the H-1B program, but the F-1 OPT program. F-1 OPT (post graduation training) hiring is virtually unrestricted (except for its duration). Of course workers who reside abroad and are brought to the US on H-1B directly are an entirely different class of foreign workers. I cannot speak to this group.