Why does shakespeare begin this scene with hamlet offering acting lessons to the players? how does this advance the plot, develop character, or to establish theme?

Read the excerpt from julius caesar, act 1, scene 1. marullus. wherefore rejoice? what conquest brings he home? what tributaries follow him to rome to grace in captive bonds his chariot wheels? you blocks, you stones, you worse than senseless35 things! o, you hard hearts, you cruel men of rome, knew you not pompey? many a time and oft have you climbed up to walls and battlements, to towers and windows, yea, to chimney-tops, your infants in your arms, and there have sat40 the livelong day, with patient expectation, to see great pompey pass the streets of rome. which summary of the passage is the best? marullus asks a lot of questions, such as, “why celebrate? what has caesar done? who is following him to rome? don’t you remember pompey? ” then he says that everyone is cruel because they do not remember pompey. they forget how they praised him and would climb to the highest places, carrying their children, just to catch a glimpse of him. marullus regrets that the people are celebrating caesar and is insulted that they forgot how they used to praise pompey. marullus thinks that the people should celebrate caesar the way they used to celebrate pompey, and that they should be in awe of caesar’s greatness. marullus remembers how the people climbed walls, battlements, towers, windows, and even chimney tops to see the great pompey.