Subjective morality wouldn't be morality anymore. It would mean that all things we consider "ethical" are arbitrary, that right or wrong is dependent on the state of the subject (e.g. victim of a rape).
Suppose someone tells you that rape is ethical. If you are a moral subjectivist, you wouldn't (or shouldn't) try to say that it is unethical, because whether something is ethical or not is dependent on the person considering it. Yet virtually every rape victim would feel traumatized by the event.
Moral subjectivism also means that whether something is ethical or not, depends on the state of the perpetrator/victim during the event. Under this system, an angry person can justify killing his boss just because he thinks it is ethical to kill someone who made you angry. Imagine what kind of turmoil this can evoke in the world if all laws were based on this philosophy.
Depending on what you mean by "evidence", there could be sufficient evidence for objective morality.
Just because everyone holds unique morals does not make morality subjective. Objectivity is in the first place independent of humans' opinions. Objectivity depends on the object. Whether the Earth revolves around the Sun or not, depends on the position of the Earth and its properties, not on what we believe about the Earth.
Last edited by Rimuel; 12-11-2011 at 02:46 AM.