The biggest problem with Objectivism isn't inherent in the philosophy. It's that too many people, once they call themselves Objectivists (or anything-else-ists), stop thinking for themselves (which is what Objectivists are supposed to do) and instead strive for conformity to the tenets without comprehension. In doing so, they miss the whole point. It's like Life of Brian: "Yes, we are all individuals."
Discussion
As an objectivist, i agree with this, the course offered by ARI in objectivism does a great job of deepening understanding so that people don’t fall into the trap of mantra repetition as you you point out. I think it’s due to the complexity of the philosophy, it’s not like libertarianism which is a social system, useful amongst others but useless on a desert island. Objectivism is an entire philosophical system, metaphysics, epistemology, ethics, politics, economics, art. It is a guide to life for an individual to be able to live a benevolent life should they choose, whether they’re alone on a desert island or in a city of millions.