[phpisthebest]

I call it violence when

1. The level of taxation is not connected at all to the cost of the externality. You know the externality exist so then you level that as the justification.

2. The taxation being collected is not being used to curb the harm of the externality, instead it is being used as a punishment for those that need or choose to use something the government has determined to be "bad"

If you want to ride in on an ethical horse of attempting to recover externality costs then the regulation needs to be done in such away that it both ties the amount of taxation to the actual cost of the externality, and any money collected from that taxation is used solely for the mitigation of harm caused by that externality