Citing ladder play by one player as the only evidence for this brokenness is also not enough imo. Excal is clearly a way better player than most other ladder-players so a lot of those wins could just be down to him outplaying.
Not to mention that after watching most of those replays the issue usually wasnt froslass snow cloak Ability but rather its combination with some sort of paraflinch.
The ladder play is evidence that something can go wrong, and we want to stop the damage there before it bleeds into an SPL game. We've seen firsthand in SPL that players have abused evasion abilities to their benefit.
I also want to correct a few misunderstandings from your post:
1) The Froslass user in that replay was not Excal, but instead was Shing.
2) The purpose of the replays was not to show who the better player was, but instead to highlight the problematic aspects of Froslass irrespective of who the user was.
3) You haven't watched those above replays that I linked, because if you did, then you'd see in those replays there was no parafusion that was abused by the Froslass user. Please watch those replays. I intentionally selected these replays so that the issues with Snow Cloak would not be masked by parafusion.
Without multiple high level tournament games decided by hail-lass i just don't see any reason to prematurely ban this mon. Banning for what it "potential could do" is a slippery slope and if we do that then we might as well ban the elephant in the room in Jirachi because that Mon has been doing "Froslass"-level of bullshit for years and is basically top 3 in usage. That should be way higher in priority than a lowly BL mon with almost bo usage. (Not that i think that Jirachi deserves to be banned right now.)
Maybe the crux of the matter is also not Froslass itself but paraflinch? Atleast going through the replays Excal provided a large amount of them were lost due to paras rather than misses.
And using SPL teams that autolose vs those froslass teams is also arguing in bad faith because those teams
a) dont always are the most solid but sometimes just finetuned for a specific weeks opponent (bo1 mu fishing!)
b) froslass was on noones radar so ofc teams wouldn't be prepared for it (thats like saying oh no u lose vs this specific uu-mol w this set thats never seen in ou - unviable team!)
I don't think there has been a requirement that we need multiple high level tournament games in order to ban something, but do correct me if I am wrong. Snow Cloak's evil twin, Sand Veil, was banned completely after it saw usage in two SPL games. One game was won by the Sand Veil user, but the other game wasn't. "Swagger" was also banned with just one game usage in SPL. The "potential could do" is a good enough argument for me when there are sufficient odds for it to luck its way through and there isn't reasonable counterplay. It isn't a slippery slope and the tiering rules ensure that this won't be the case.
Jirachi and paraflinch/parafusion are its own beasts, and while this isn't the topic in which to discuss this, you're more than welcome to suggest what changes you would like to propose within the tiering framework instead of simply saying "do something." I genuinely would like to hear how you think these issues can be resolved, and we can discuss this in the DPP discord server (https://discord.gg/C4NPYZ65Tp).
Regarding points 'a' and 'b' in your post:
a) A team being solid has no bearing on whether it will miss its moves vs Froslass. It just comes down to luck.
b) No one is saying that you can't prepare for Froslass. It's possible, by using a sand-setter like Tyranitar or Hippo, or having a weather-changing move (like Sandstorm, Rain dance, or Sunny day) as a 4th move slot, but players shouldn't feel forced to resort to these measures to address Snow Cloak abuse.
Tackling Froslass first just to adhere to a streamlined tiering policy framework is nothing short of lazy and makes 0 sense. Doing so by council decision without a proper suspect test turns a bad decision into a very bad one.
Especially when the pro-ban outcries wherw mostly contained to just Excal and seemed to have little public support otherwise.
It is a shame to lose a cool mon such as Froslass that has other neat sets (spike support as lead for example) just like this.
If Froslass really is DPP's issue #1 rn (its not lets be real) then atleast hold a suspect test for it. Dont use SPL being soon as a cop iut - with sign-ups etc. there is more then enough time still til the start of SPL w1 (3-4 weeks!).
I urge the council to please rethink this decision.
Again, correct me if I am wrong, but we haven't used a suspect test for banning uncompetitive moves/abilities (see Sand Veil / Swagger).
If you wish that moving forward that any ban occurs only after a suspect test, then you can advocate for that separately.