Firstly, Froslass beats Ambipom if it's bulky, and Froslass always beats Uxie. Next.
Arguments that resemble this below do not hold much ground:
"Pokemon X is not broken because Pokemon Y can possibly run this never used / terrible set of A or B and Pokemon Z can also run this bad set C and if M, N, and L happen before Pokemon X switches in it can lose"
This also applies to Pokemon you would not even dream of unbanning in Ubers, such as Kyogre.
"Kyogre is not broken because you can run Parasect in Ubers and if you don't switch into entry hazards and Kyogre doesn't have Ice Beam Parasect can win."
Your examples with Donphan and Claydol are horribly false as well. Claydol's Shadow Ball doesn't 2HKO, it barely 3HKOes iirc while Froslass can just sit there Spiking and Pain Splitting then KOing with Ice Beam. Donphan is OHKOed by Ice Beam as well.
Blastoise can 3HKO Froslass, but when the only common spinner that can be Froslass is left with 40% after KOing Froslass (Pain Split), you know you have a problem. After this Froslass can simply send in Moltres or Swellow to threaten or KO Blastoise. Once it switches in again it will have 15%. Good Luck.
Additionally, you are saying things like "Froslass takes time to set up Spikes" as an argument which I cannot comprehend. Froslass being able to take time to set up Spikes is absolutely not an argument against Froslass being BL.
Moltres and Swellow are weak to Stealth Rock, yes, but why can't you run it with your so-called awesome Rapid Spinners? I mean, if the opponent isn't using Froslass Rapid Spinning will usually not be a problem for Pokemon such as Donphan. Also, "weak to SR" is not a valid argument against something being broken (see Yanmega and Honchkrow).
See, here's your problem, and it's a fallacy that you've been repeatedly using over and over in your ridiculous crusade (yes, it's qualified as a crusade at this point) against Froslass: that you always want to switch a spinner into it.
Switching a spinner directly INTO Froslass is rarely a good idea, as you've pointed out in every post you make, but you neglect to mention that there are many offensive threats that Froslass cannot touch, especially the bulky set, that simply set up on Froslass or kill it and leave you minus one spiker/spin blocker.
For example: Sunnybeam Moltres (a common enough set) comes in on Froslass's Spikes. Roosts off SR damage on the switch to...let's say Milotic as a common enough example, uses Sunny Day to take (36.14% - 43.61%) from the min SpA surf, then does (69.54% - 82.23%) back, an assured 2HKO with time to Roost off the LO damage and keep rampaging through your team.
NP Porygon-Z works the same way, as does CM Cress, SD Scyther (if you run Shadow Ball over Ice Beam), NP/CM Missy (especially if you run Ice Beam), NP Toxicroak, etc, etc.
This is why pure offense has little to no trouble with Froslass, she only causes problems for Stall and Semistall because they rely on switching and countering much more than pure offense. So if Froslass is only trouble for a specific subset of teams (who often run her anyway, thus largely negating the impact) then I don't see how it can be BL.