Staraptor happens to outspeed Kyurem. A OHKO after rocks. Last time I checked if something could OHKO you and outspeed it was at least a check. Not saying it is a counter but it is completely able to revenge kill it.
What are you supposed to do when it hopscotches in on the revenge or on something that can't hurt it? All bulky Water-types, all Grass-types, most walls save for Registeel and Brozong, Zapdos, most Raikou, things slower than 90 base Speed, etc. Are we to count on Staraptor to regulate a Kyurem metagame?
Which brings us back to the idea of beating fucking Staraptor. Good luck.
Sun equaled out by Hippodown
Kyurem able to check Hippodown/Roserade core
Staraptor checked by Hippodown
Kyurem kept in check by powerful sun sweepers/Staraptor
We will not unban any of these things.
252 SpAtk Life Orb Azelf Shadow Ball vs 252 HP/0 SpDef Deoxys-D: 48.68% - 57.24%
Not a 2HKO most of the time due to Leftovers recovery.
252 SpAtk Life Orb Nidoking Shadow Ball vs 252 HP/0 SpDef Deoxys-D: 49.34% - 57.89%
Not a 2HKO most of the time due to Leftovers recovery. Shadow Ball is extremely rare becase of the other targets he needs to cover, and you will run out of Shadow Ball before he runs out of Recover.
252 SpAtk Life Orb Mismagius Shadow Ball vs 252 HP/0 SpDef Deoxys-D: 65.13% - 76.97%
Most Mismagius do not use Life Orb.
Aside from those discrepancies, I believe the meat of your post is
Lots of pokemon that 2HKO Deoxys... Tell me how exactly Deoxys gets a chance to set up spikes?
Ambipom (sans Taunt)
Bronzong
Dusclops
Empoleon
Flygon
Hippopotas
Milotic
Nidoqueen
Porygon2
Registeel
Rotom-H
Slowbro
Snorlax (non-CB)
Suicune
Swampert (non-CB)
Togekiss
Umbreon
Zapdos (Defensive)
16 Pokemon, which is exactly 1/3 of the tier, when it is not investing fully in defenses. If it went 252/252 HP Bold, you can remove the annotations from Swampert, Snorlax, and Flygon. With 252/252 Calm, you can remove the annotation from Zapdos and add Sub CM Raikou and Nidoking. He also sets up on Gligar, who is not UU at the moment, but is receiving a lot of usage right now and is expected to be UU next month.
Considering that one or more of these Pokemon are a staple to most UU teams, the fact that other decent RU and below Pokemon that might show up every now and then were not counted,
and his ability to set up on his checks while locked into a favorable move (Heracross into anything but Megahorn, Krookodile into anything but Crunch), Deoxys is looking to set up on something every game.