Originally Posted by Trzeci_Wymiar
I'm sure "dialect" could be used loosely to subsume argots, it's a very generalized term that has no real meaning at the level of the nitty gritty other than "variant."
Mirriam Webster, in fact, shows as its second definition for dialect: "The language peculiar to the members of a group, especially in an occupation; jargon: the dialect of science."
Argots, jargons, dialects, they can be used synonymously.
So it's not a HUGE mistake, in fact it's not really a mistake at all.