“We oppose Mormonism, its false doctrines, and publicly communicate such to others, because we love our fellow man as ourselves and wish others not to fall into the same sin as Mormonism projects upon its adherents.”
...meanwhile, Mormonism continues to prosper and grow. And no wonder! What you have is a marketing problem. You should say “Use Brand ‘X’” instead of saying “Don’t use Brand ‘M’”.
That’s what the Mormons do. Are they that much smarter than you?
I don't know. IMHO, God is the one who does all the work in salvation. If Mormonism is growing, then He has already made plans that quality through faith is much more superior than quantity in religion adding to anything He has already provided.