it doesn’t frankly. And more likely a government reaction. During 9/11 we were met by National Guard aircraft and escorted to Fairbanks AK. Which did nothing other than put the sh@ts up the pax. I’m pretty sure they’d have splashed us if we’d deviated in the slightest from their instructions. For good reason on that occasion. Can’t see how it helped with this other than peeing away more of the budget. ‘N

Because they need to be sure it is not an attempt to hijack aircraft, rather than just an unruly passenger.
ATC were not to know the exact situation in cabin.
One report said pilot in radio message said “cockpit secure”, which presumably rather than reassure ATC made them feel cockpit breach had been attempted. Further reports say passenger rushed at cockpit door before restrained.
Not saying she attempted to hijack, but ATC are playing it safe.

The security services on the ground don’t necessarily know that it’s just some chav whos had too much too drink.
They may well have to assume it’s an attempt at a breach of the flight deck, and since 9/11, do you really need it spelling out as to why the typhoons are there?

Kill it if it becomes a threat to people on the ground. It probably won’t but history suggests it could.

I'm guessing that the RAF wanted an excuse to test out their reaction time and had a word with air traffic for a heads up next time there was a minor incident such as yesterday,

I used to rely on gate staff, handling agents and cabin crew to screen these idiots from boarding. If there was any doubt then they would not be carried on my aircraft. Problem lies in the availability of booze 24/7 allied to the fact that the first thing the airlines do is offer passengers alcohol regardless of the time of day. I never had to divert for unruly pax but on numerous occasions I made sure that they were met with friendly local police whose modus operandi may not have been quite as politically correct as in the UK !

The airline involved here do much of what you have suggested. There isn’t time to breathalyse every single passenger, but facilities are available and have been used to breathalyse people suspected of being inebriated and they have been then prevented from flying. Sales of alcohol are restricted to a set time of the day, still early mind, and are monitored and restricted by the Cabin Crew (or should be, they are taught to do so). The airline has also been instrumental in some airports sealing duty free sales in tamper proof bags to try to eliminate people drinking this, not a perfect solution, but every little helps. It would be down to the airport to instigate a delivery service to the aeroplane like in the US, and there seems to be a reluctance to go down that route.

The airline involved here also prosecutes these imbeciles, and delivers the bill to them for the expense incurred. I’m sure this lady (if you can call her that) will end up in prison after this event, she won’t be the first that this airline has pursued and seen sentenced:D:D