The mall is not "public" like a city town square. It is private property.
If the mall owner does not want religious recruitment, he need not allow it.
OTOH I live near a "public" place which has for decades, been the site of religious recruitment. People walk around carrying crosses, palm fronds, sitting/standing to hand out brochures. It is taken to be a part of the "scene" at this public beach area.
Having said this, IF the recruiters were to Get Up in Faces, not back away, not leave folks alone, they would most certainly be warned, and made to leave if not following direction.
So this X-muslim, now Christian fellow may have gone too far, broken rules.