First, it undermines your personal freedom.
If you accept and never question the moral beliefs handed to you by your culture, then those beliefs are not really yours—and they, not you, control the path you take in life. Only if you critically examine these beliefs yourself and decide for yourself whether they have merit will they be truly yours. Only then will you be in charge of your own choices and actions.
Second, the no-questions-asked approach increases the chances that your responses to moral dilemmas or contradictions will be incomplete, confused, or mistaken. Sometimes in real life, moral codes or rules do not fit the situations at hand, or moral principles conflict with one another, or entirely new circumstances are not covered by any moral policy at all. Solving these problems requires something that a hand- me- down morality does not include: the intellectual tools to critically evaluate (and reevaluate) exist- ing moral beliefs.