Aside from what I (correctly) cited from the Ramah and Shach in Hilchos Talmud Torah, Nnne of this “living off tzedakah” material has anything to do with kollel people. This is a common error. Tzedakah means that I give you money for no other reason that you need it – I do not demand anything in return for my donation. If I do demand something in return for my donation, it is not a donation but payment for services rendered. So if I pay you to entertain me, to be my personal trainer, to sing and dance for me, to be my baby sitter, I am not a baby sitter living off charity, but rather a paid worker. And so the statements about people living off tzedakah refer to people who are given money because they are poor, with no expectation from the donor that they learn, or work, or sleep, or do whatever they want. However, if someone gives money to you because he wants to merit the zechus of supporting Torah, and expects you to learn Torah because that is what he is supporting you to do, then that is not tzedakah at all but rather a simple business deal, the same as if I pay you to play baseball.
If I give you tzedakah money because you are poor, and you sit home all day watching television, then you may be an unproductive member of society but you are not a thief – I gave you tezdakah for food, and you are spending it on food. It was my choice to do that. But if I give you money to learn in Kollel and you stay home all day watching TV then you are a thief, because you took money specifically to learn and you did not keep your end of the bargain.
Thus, taking money for learning in Kollel is NOT living of tzedakah. Since I, the recipient, must provide something in return for payment received, that is a simple business deal. If I do NOT have to provide anything in return for payment received, that is Tzedakah. Since Kollel people must learn Torah in return for the payments they receive, they are NOT living at all off Tzedakah. Not any more than any person who renders services for payment received.