It feels like, this whole time, this whole play, the Queen’s been pretty skeptical of this whole mad show Hamlet’s been putting on. She knows her son – knows the background and is generally pretty spot on about the general cause (aside from the murder of her husband part.)
But here, she sees her son suddenly start talking to angels and a ghostly figure and she stops resisting all of the voices that have been proclaiming his madness.
This is a surrender to what everyone has said. This is a bowing to the crowd. This is a resignation.