I think part of the difference in approach can be explained by the arrival of the 386 processor. At the time Stallman makes his announcement he needs Unix works

I think part of the difference in approach can be explained by the arrival of the 386 processor. At the time Stallman makes his announcement he needs Unix workstation vendors to donate their proprietary hardware for him to work on, because at that time that was the only way to get a running Unix environment. By the time Torvalds makes his announcement you've got 386 processors widely available, plus Minix as a viable and cheap (but not free in either sense) alternative to Unix running on top of it. In some ways you could argue Stallman's approach was disrupted by the arrival of cheaper commodity hardware.