I have a manual of St. Vincent De Paul. (old one) It may be different from the Legion of Mary or the Blue Army. Here is the surprising twist. I would say that most of us think of St. Vincent De Paul group taking care of the poor/needy. Well, guess what, that is not what St. Vincent had on his mind! He and others went door to door making sure that everyone had access to the sacraments. My Aunt was of the Blue Army and that is exactly what she did. This manual made no mention of feeding the poor. It was understood, that if there was a need of food, it just might be that the family was in need of supernatural help first. If those needs were taken care of, then God would show is mercy and etc, if you get the idea that I am trying to get across.
The reason why ST. Vincent De Paul is what it is today in the New Order is because it is not catholic owned and operated, it serves the Federal gov't. I found that out in 1992, and I am sure it was like that for decades before.
Besides, what use are they when there is no sacraments in the New Order and why should there be a mission to convert when New Order is accepting of all sects.