Morality As a Limit
One of the consequences of subjectivism is the belief that values are subjective. This means that values are whatever we choose to pursue and whatever we desire. It means there is no such thing as good or evil, except what you think is good or evil. If you believe something is evil, that's just your own personal preference. It is not, and cannot be, a statement about reality.
The idea of values being subjective is a denial of the need or possibility of morality. Since any values can be accepted without consequence, there is no guide to determine which values should be accepted. Since there is no objective moral standard, reason cannot be used to determine how one should act. Emotions are all that is left to make the decision, and subsequently, one is ruled by one's emotions.
A second consequence to espousing subjective values is a demand for no moral judgment. Since morality is subjective, and right or wrong are not real, it makes no sense to judge others by your own personal moral whims. And when moral judgment is not practiced, justice is impossible. Crimes cannot be punished. The innocent cannot be protected. It is easy to see who benefits from this policy.