They are completely different situations.
It is very clear cut in my mind.
Harry does not LIVE in the UK.
He lives in the US, which is his choice.
Should he decide to move to the UK permanently again no doubt there would be a conversation around his security arrangements. There is no way UK tax payers should stump for 247 security in another country, when he has chosen to abandon the UK and his royal duties of which he has had the best part of forty years of tax paid luxury already and the best of everything all funded by us. His choice to move to the US and his choice to fund his own security. No question. As and when he is here to for functions connected to the royal family, security is ALREADY included, as we saw at the funerals and jubilees.
Prince Andrew lives in the UK. He is an obvious target and he is the Queen's son. This is being paid for privately by the family not the tax payers. I have no issue with it. I imagine it was the late Queen's wish that this should be provided.
It is like comparing apples and pears.
If Harry moves back, a conversation can be had about his security. If he chooses to stay in the US the onus is on him to provide it.