well we can't just cherry-pick 3 banned mons and call it "not a coincidence", we'd have to look at the other banned mons too. there haven't been that many setup mons banned. it's basically just those three and bloodmoon, and sneasler, and baxcalibur, and chien-pao, and espathra, and firepon, and terapagos, and palafin, and urshifu-rs, and annihilape, and archaludon sorta, and flutter mane and chi-yu even though it wasn't the only reason, and formerly roaring moon, and almost kingambit and zamazenta, and sleep whose biggest abusers were setup sweepers, and possibly soon gliscor again, and…
ok yeah maybe there's an issue here
To be fair, a lot of these
were problems. I'll go through a few examples that were listed.
Terapagos was mega broken. Its Double Dance and other setup sets were incredibly potent, thanks in part to its ability Tera Shell giving it a free turn to set up if it's at full health. And even if it was chipped prior, Terapagos still has pretty good bulk (95/110/110), so it could eat a hit, at the very least. It could also play the role of a general offensive mon or lean into a more supportive role. It has an absolutely massive movepool, and it definitely put it to good use in its time in OU. That's not even mentioning its Stellar form. I think this statline coupled with what this form does to Terapagos's moves, along with the roles it fills regardless, is enough reason to justify its departure from the tier...
Oh, also, Tera Starstorm becomes a completely unresisted move once Terapagos decides to Terastalize, and if
you're Terastalized, it becomes super-effective against you. So there's that.
Ah, the days when Mega Weavile ran amok in SV OU... Those are days I really don't want to remember. Chien-Pao is, quite frankly, an insane mon. While 120 Attack isn't too outrageous of an offensive stat this gen, it gets an incredible offensive STAB combination, an ability that effectively bolsters its attack even more, and a speed tier that's only beaten out by a few things... and even those things can lose to it. Swords Dance Chien-Pao is an extremely deadly sweeper, and Choice Band sets can muscle through just about anything. Chien-Pao also loves Tera, as it can either make its raw power even more ridiculous, bolster its coverage, or resist/be immune to a hit if it really wants to. It doesn't need Tera, though, and it can function on its own just fine.
Annihilape was... well, really annoying while it lasted. It's bulky, it has effectively perfect coverage with its STABs (discounting HZoroark), it has longevity, and it has Rage Fist. As opposed to the other two here, Annihilape was really only a setup mon. It's sort of like Okidogi, but instead of being fun and cool it's just super egregious. Bulk Up makes it really hard to kill on the physical side, and it has enough natural bulk to comfortably eat a special hit or two. Taunt also prevents opposing setup or disruption, provided that you actually get off the move. Drain Punch gives it a way to hit hard and recover health at the same time, and Rage Fist is... well, Rage Fist. It goes from being kind of bad to really good after you take a single attack and it only gets better the more hits you eat, going all the way up to
300 BP. Annihilape doesn't die, and it refuses to die even harder after Tera. Shedding Fighting/Ghost's weaknesses for a better defensive typing like Water helps this scary little simian a
lot.
"Why do you keep bringing up Tera?"
I'll go ahead and answer the question nobody asked. Tera breaks broken mons more. (Try saying that five times fast.)
While Tera
is pretty readable, and while you can absolutely work around it in most cases, Tera is a very strong option when used effectively - especially on mons that were on the verge of being busted or were already overpowered. I'm not trying to advocate for any action on Tera itself, but Tera does seem to be really good at pushing things over the edge (or making them even more bothersome). It was just worth noting, so I brought it up.
No hard feelings, by the way - I just thought I'd throw in my two cents for once, rather than posting basically nothing.
(Also, if that was a humorous post and it went straight over my head, sorry!!! I'm trying my best out here, I swear...)