@Nothing spiteful about it.
They’re not working royals. They’re private citizens. They don’t live in the UK. Nothing that they do represents the Crown or Great Britain. Meghan isn’t a British citizen.
Other members of the RF go about their daily business with little to no security, and have no problems whatsoever. The heir to the throne & his wife regularly interact with large crowds and have no problems.
So why should British taxpayers be strapped with the costs of private security for an estranged prince who doesn’t represent anything but his own interests, especially outside of the UK?
Why can’t Harry pay for his own security? Why does he need other people’s money to do it?