C.S. Lewis takes on the issue of subjectivism in his book "The Abolition of Man". He takes a pretty close look at the ethical repercussions of moral subjectivity. It's a fairly quick read and I think it's even available online because it's out of copyright.

It's not by any means a direct rebuttal of your comment, but right at the beginning of the book I think there's an example that's germane to this current conversation. You may find it interesting.