Clientelismo es a sad reality, not only from Argentina but of the continent. They just take advantage of ignorant, poor people.
This said, if we see this as a sociological problem, we must say, that this is a simple and plain exchange of favours. This is politics, the real meaning of politics. I give you something but you give me this other thing. Quite simple. Is this the way democracy was planned in its origin? probably not, but everybody deserves to vote whoever they want, and if they chose to vote someone who gives them just a choripan for a vote, well, that means that nobody could offer more, so its better a choripan than nothing.