Fines and taxes are two very different things.
Going back to the Colonial Age, when colonists traded with the French behind the governments back, it was considered an acceptable punishment to heavily fine them. The smuggler, as far as the colonists were concerned, deserved to go out of business. When the British government decided it was okay for the 13 Colonies to trade with French colonies, they greatly lessened to payment due to the government for the trade. At that point it was a tax and even quite profitable. Parliament did this to get colonists to accept a tax. The colonists still balked at it. The British government had no right to tax them without proper representation. Fining them was a different story, since it was over a 'crime.'
This situation is a bit of the reverse. SCOTUS is trying to claim a fine is a tax, in order to keep the law intact. No one is going to believe it. Fines and taxes are not the same thing.