Basis of morality is identify of an individual. Without agreeing to what constitute I vs rest, we cannot even start to talk about morality. From individual you derive natural rights starting with his/her body proper. And then if he/her mixes labor with any previously unowned natural objects then the that becomes the property of that individual. Thus, you derive individual rights and the concept of morality. Thus, morality is to me is simple: Thou shalt not steal, Thou shalt not commit murder and all individual rights that are consistent with the above principles.
If somebody says to me that he disagrees with this and each person could have his/her own moral philosophy then I would reply: what does he/she mean by "each person"? Unless you define an individual and his sphere of influence (property) you cannot even conceive of having subjective views.
Thus moral relativism itself require absolute belief in individual identity (otherwise what do you mean by "subjective" beliefs and views?).