Well, i try to explain.

To participate in a giveaway for a dlc, steamgift checks that you are the basic game, otherwise you cannot participate.
steamgift uses the steam api to check this but the steam api does not provide information about games that are in a limited profile, so steamgift considers that no one has the game.

So no one, whether they really have the basic game or not, will be able to enter your giveaway as long as the game is in limited profile.
I hope it's clear :)