Sure, but that's not the way it's generally interpreted in the modern parlance.

Agreed that what you note is the general interpretation. Also agreed that the statement, when so interpreted, is entirely different -- and, I'd think, is untrue. In other words, I'm suggesting that the "general interpretation" perverts the meaning of the maxim.

Bartleby, http://www.bartleby.com/68/30/2330.html more or less supports the reading I gave above.

But on further LIU I suspect that the original meaning is completely different. Cicero: Quod si exceptio facit ne liceat, ubi necesse est licere, or roughly, [help me here, faldage] "That which a special provision makes illegal in some circumstances, is thus [by inference] shown to be legal in all other circumstances." There are old English law cases that express this as Exceptio probat regulam de rebus non exceptis ("The exception proves [confirms] the rule so far as concerns the matters not excepted.")