What was Hamlet's opinion about his mother's remarriage? Why?

Hamlet is absolutely scathing over Gertrude's remarriage. Why? Well for one thing, it's come much too soon after the death of her first husband, King Hamlet. Prince Hamlet is still brooding over the death of his father, and yet here's Gertrude moving on quickly with her life as if nothing's happened. Hamlet is in mourning for the death of his father and doesn't see why anyone else shouldn't be.
The second reason for Hamlet's hostility towards Gertrude's remarriage is that her new husband is the wicked Claudius, the man responsible for the murder of King Hamlet. Young Hamlet never liked Claudius to begin with, but he likes him even less now that he's discovered that he was the one who murdered his father as he lay sleeping in the garden one day.