This is supposed to be so that he can defend the court case in the US as a private citizen. Presumably so RF and the military are not dragged in to the mire.
I don't think she could have done differently. She will want to minimise the damage to the Crown I feel sorry for her as a mother, regardless of her position and culpability in his upbringing. Her supposedly favourite child has let her down. I have no sympathy for Andrew. He reaps what he has sown.
You have to admire our Queen, This must have been a tough decision to take against Andrew who is thought to be her favourite child but she has acted straight away and stripped him of his military and HRH title. He will continue with the court case as a private citizen. Shame our PM hasn't the same courage.