Piggybacking on some points already made, "Mega Sableye invalidates hazard setters" is a huge overstatement. It's Magic Bounce that does this on any mon in a vacuum and a total invalidation of hazards is only possible vs passive users than can't touch Sab anyway. Even in OU the only 'mon that gets free hazards vs it is Mold Breaker Exca and the tier has far more viable hazard setters than that, passive or otherwise, meaning as long as there's reasonable counterplay available in UU a 100% hard stop to what Sab does isn't necessary.
Yeah Sab donkey punches Froslass Spikes stack, thereby the current HO structure, but idk if that alone warrants an outright ban. Sash/Custap Diancie makes a decent fallback lead for HO, for one (inb4 Skill Swap Azelf lol). UU has both an abundance of viable Fairy-types and plenty of raw power to dispose of Sab. Again I'll bring up Diancie, which was already on the rise before Sab dropped and is prolly one of the best answers to Sab currently. MAlt is in a similar vein.
As Sab usage rises, a rise in offensive rocks setters like SD Steelium Cobalion, SD Terrak, Groundium Krook and a few niche ones like Mamo and Nidoking would be viable. All are capable of sets that OHKO/2HKO Sab outright or with some chip depending on its defensive investment, so the hazard 50/50s Sab creates are often in the rocker's favor, not its own.
Sab is a really good, really annoying presence for balance/BO builds but it's hard-pressed to solo hazard control for the entirety of matches on a consistent basis like some are claiming, at least unassisted by teammates. Stall teams appreciate the hazard control as well but foregoing other Megas opens up weaknesses to other threats thanks to Sab's lack of meaningful resistances (as already touched on). I'm for the QB argument regarding the ladder tour, but after I think this troll deserves a fair shake down here before the "brainless," "overcentralizing," etc labels start circulating.