This means that a theory which leads to imposing moral standards universally without regard to people's historical and psychological differences are based off of subjectivism and lack any form of thorough investigation(normative science). This is self explanatory in the question where it says "...postulates moral truths enunciated by self-evident intuitions that are unchangeable". Moral standards such as this are mostly based on traditions that are subjective and are not given to transparency. This is opposed to when questions may be asked and investigations come into play as to why a particular moral opinion is taken enabling a society appreciate or understand a moral stance based on it's historical, cultural or psychological origins.
They wanted equal treatment that the people in Islam had that they weren't given in Hinduism. In Hinduism, each class is treated differently, the lower class treated the worst.
