Yeah, people already know that it's broken. I think it's getting banned because that Pokemon with Torkoal regardless of doubles or singles is very strong.
Before it gets banned, there is counterplay of course
Switch Scizor in on Moonblast
Switch Kingambit in on Shadow Ball
Grafaiai has good typing coverage against Flutter Mane
Clodsire is the best tank against Flutter Mane
Garganacl can take a hit from Flutter Mane and hurt it