Is it a political knee-jerk reaction? Its actually not that easy to find any politicians making anti display statements (unusually few I thought).
Think its more a case of good practice by authorities to review in the light of two fatal crashes of vintage jet aircraft.
Really, its bad/very negative for the military because they are dragged into an affair that really is not of their making.
As I've pointed out before, and been viciously attacked for on here for daring to go against the herd, the many crashes generally involve old/ex/former/used military aircraft and former military aircrew that simply aren't operating/flying to the very high standard required.
The future for the military to host "air days" will be fly-in static-only display open days. Much safer, far lower risk.
People will still come, in fact if the military could get its act together properly and gather many, or all even types of current UK mil craft, with their crews to actually meet the public, then I think they would be on for record cash-generating crowds.
But yes, in the current form its the sad end of an era.
For Martin the Martian, at least two aircraft crashed either onto or directly adjacent to main roads around RNAS Yeovilton in recent times but not on air days. In 1985 a twin seat (T4?)Harrier crash and double fatality right next to the A37 just to the north of the field (think it went through the hedge at the roadside, used to be a gap there). Also a Hunter in 1988, pilot ejected over the A303 after staying with the aircraft, the aircraft then hit a cow field on the north side of the A303 and then travelled (intact) right across the B3151 scraping the tarmac, smashing through the hedges and coming to final rest in a large pile of manure. Think both spots were within the MATZ.