I wonder why Hamlet goes about this this way.
It is a rather roundabout way to talk about what is happening here. I mean, Gertrude has two legitimate concerns: 1) her son has killed a high ranking official without much remorse 2) He’s talking to the air, which he says is the ghost of his father.
The ghost has asked Hamlet to step between her and her fighting soul, which I take to mean that he’d like Hamlet to comfort her – which he definitely does not do.
If this scene went logically, Hamlet would say, “Hey – Dad’s ghost came to me and told me he was murdered by your husband. I’m supposed to exact revenge. Are you with me on that point or against me? Did you help him or didn’t you? I have a ghost whose word I trust. We’re dealing with a murderer here.”
But instead, he spends the whole scene blaming her. This, of course, makes for an interesting scene. But I am curious about that impulse to evangelize and accuse his mother in a moment where he could be explaining. Maybe he’s distraught about killing Polonius and is trying to shift responsibility for it away from himself – as in, “O you think sticking my sword in an old man is bad – well…you …you sleep with a bad man. So it’s YOUR fault.”