OP, along the same lines of compiling a list, there are numerous RV lifestyle blogs. You could more/less establish a blog for your travels, which might include a section that provides information related to campgrounds that are fitting to large families. I don't see how this information could harm anyone. Unless I had complete animus toward large families, I would never do an Internet search targeted toward finding CG's that allow it only so that I could avoid them.
FWIW, I would rather have my campsite next to a large family of well-behaved children vs. 2-4 adults that stay up all night partying under their awning.