Why does the audience feel sympathetic with Hamlet’s quest, but not Laertes’ quest?

We simply do not know Laertes as well as Hamlet. Laertes remains on the periphery of the story until around act 4. We have gotten used to Hamlet's musings about good, evil, the nature of life.... before Hamlet ever considers violent revenge. Laertres is quick to anger and shows up from France all of a sudden all hot and bothered about his father's death Laertes lacks the insight and reflection of Hamlet that the audience has come to appreciate.