Most are uncomfortable talking about this because we're humans and have compassion. On the surface, it seems like a mean spirited thing to suggest that tolerance and social programs have unintended consequences and are detrimental to the recipients. An example is how welfare has often become a surrogate for a two parent household.
I think most would agree that obesity and (generally) single parent households are damaging to both individuals and society as a whole. How do we find a balance that doesn't allow folks to fall through the cracks, but also doesn't encourage behavior that takes a toll on human beings or compromise the sustainability of social safety nets?