Is it inappropriate to drink the cereal milk after a bowl of cereal?

My wife said it's disgusting (she doesn't like the taste) and it grosses her out when I or my daughter do it. She goes further by saying, "it's bad manners." I've looked on a manners website and found that they would only agree if it were out in public, but okay if done in the privacy of your own home. Similar to drinking your soup from a bowl.