Given that Laertes was never spied on by Polonius, that is the correct answer here. Polonius spied on Hamlet, not Laertes, and he died because of that. Laertes did feel sad about his sister's death, he did confide in Claudius, and he did grieve the loss of his father, Polonius.
Since the rest of us can't read minds, we are more influenced by the actions of others than by their thoughts.
This is pretty safe because people do tend to act on their most dearly held thoughts and beliefs.
Thoughts don't really change the world the way the actions they influence do.
