It's okay to cancel the cancellers. In fact, the expected outcome of this effort is to 'cancel' the cancellers, by not allowing their complaints to translate into institutional action. They are free to argue others should be canceled, but no one should listen to them. Given that they are currently listened to, preventing that is indeed a form of cancellation, and it's a good one. You cannot and should not expect to benefit from the very policy you denigrate.