And I remember reading that Dr. Rock (from the Boston, MA, area), the Catholic who invented the birth control pill, pulled his children out of Catholic grade school because the nuns were teaching Extra Ecclesiam. Both his children met tragic deaths. The son, against his father's advice, went to a party and died in a head-on collision.
Most people do not want to have to tell their Protestant neighbors, "You need to convert if you want to be saved." I have said it before, but when I was in the SSPX seminary 94'-97' several priests commented, "Don't preach that the New Mass is a mortal sin, how are we going to convert people over from the Novus Ordo?" The same principle in involved.