Arso: a melamed in a cheder of FRUM kids from FRUM families, as well as anyone else involved in chinuch, is doing just as an important job as Lubavichers or others who work in kiruv
Without diminishing the role, these kids have parents who have a mitzva of teaching their kids and they are capable of hiring a melamed. Those other lost kids are like orphans as there is nobody to hire a melamed for them. Maybe, if you are melamed who is teaching kids for free, or at least not differentiating between those who pay you and those who do not, then you might be comparable.
On the other hand, you are right, the “frum” people also need to be baalei teshuva.