Since the beginning of February, when Kyurem was not banned even with a 58% support.
At the time, one of the main DnB arguments was the need for Kyurem to counter Rain/Sun that dominated the ladder. Now both Torkoal and Pepipper are not even in OU, Archaludon was banned next, then Volcarona which was one of the best Kyurem ''counters''. The beginning of the OLT brought us the SubProt set, and Freeze-Dry has never stopped being a problem, with a coverage that not even Tera Blast can provide.
Kyurem has been on the rise since February when it was already broken and if there is an exception to the "rule" of waiting a 2 week period for the metagame to adapt, it should be Kyurem.
I was not won over by Ausma's arguments, because I was never exactly against his position on Tera Blast, but I have changed my POV on this. Not even Baton Pass had an outright ban, so the only way we can have a chance at a metagame without Terastal is by gradually de-characterizing it until other players can see its other negative effects. If in a future I'm until present and the opportunity arises, I will take a pro-ban stance.

Supreme Overlord with 135 atk and 100/120/80 bulk makes this Pokémon
Broken.
Sucker Punch + Terastal type change makes this Pokémon
unhealthy, with unthought-out and only guessable interactions between opponents. We've had enough of seeing Kingambit endgames. Is Encore enough? Please don't. Just wait for someone to start using Mental Herb.
Kingambit is
centralizing, it can fit as the last slot in anything other than hard stall. There's no reason not to use it. One could argue that bans and more bans will only take away the diversity of the tier, but when something is too good to be unused and forces counterplay with more than one Pokémon, we are trading a variety on paper for a practical loss in diversity.
It
encourages Broken x Broken. I see several anti-Zamazenta posts and several players saying that it can even be broken, but it is a necessary evil. This Pokémon, like Kyurem, has been DnB in the past and is in a growing development and is out of control, but it will have little support if Kingambit remains.
Pre-DLC, Kingambit
was DnB even with 55% support for banning it.
After Kyurem and then the adaptation period, I call attention to Kingambit being a problem for the tier.