It seems that no matter how much moms speak out against it, there's always going to be someone out there who's first inclination is to mom-shame them.
Since everyone is a little different, it's unclear whether a given person engaging in this activity is taking out their own insecurities on a stranger or just refusing to acknowledge that different parenting styles exist. But regardless of the reason for it, it remains a persistent problem.
But while it's annoying to receive this kind of treatment online, it can cause much more of a headache when it spreads into the family.