It's not just about Harry taking the throne, although accidents do happen. He can do more than just run the government. He could be a goodwill ambassador, He could help bring trade to England as well as tourism. He could do more charity work.
Hell, the Man could set up a kissing booth for women's shelters for 12 hours and at 20 pounds a kiss, He could do more good than He could serving in Afghanistan.
It's not so much that He was doing England a great deal of harm (though if He had been killed, it would have been quite harmful). It's just that He's not doing what is best. There are better ways for Him to help His country.
Instead He went off following His own heart with nary a thought for His position and His responsibilities.
And Primo, His responsibilities to the state are different than the vulgar mob's. He is royalty, of a different blood so to speak. He is beyond mere men and has responsibilities beyond that of the average man. He simply hasn't realized it yet. Though in time, I'm sure He will.
@Flint
I don't need to dance in the fires to understand that they're hot. A doctor doesn't need to contract a disease to understand it. And believe it or not, to understand people, you do not need to interact with them.
Even if it were the only way, there are still better ways for him to do so that would be of more benefit whilst protecting the royal line. Charity work for instance. Volunteering.
To serve is to survive