Romans 14 begins the conclusion of Paul's letter to the many Christians scattered in a smattering of homes around the Imperial city. Because of the great diversity of believers, Paul needs to address some ethical and moral issues that were constantly arising. Being in Christian community has never been easy, and apparently from the very beginning different people had very different and stron opinions about what was - not just approrpiate or polite - but morally right or wrong, ethically offensive to God.
Here Paul specifically addresses the controversy around eating meat and only vegetables; and around regarding one day special and regarding every day sacred, but the real issue is around the food and drink. Many devout Jews have converted to Christianity, and they have brought with them their rich and enormous food traditions/taboos with them. Some of the Jews want to incorporate the Torah/Talmud regulations on food into their new Jesus-faith; and other Jews want to leave them behind. To make it more complicated, some Gentiles who had converted to Judaism, have now converted as Gentiles, out of Judaism into Christianity, and some of them have left behind the food regulations and others haven't.
I can't imagine how hard it must have been for observant Jews/Gentiles to eat what they considered unclean meat. Unclean meat could be that which was improperly slaughtered, or it could be that which was sacrificed to an idol and then sold in the marketplace. And I can't imagine how gleeful some observant Jews/Gentiles were to leave those regulations behind and enjoy their new found freedom in Christ. They, like Paul, were fully persuaded in the LORD Jesus that nothing is unclean in itself. All things are permissible, though not all things are beneficial. What freedom.
So it seems only obvious that those new believers who are drawing upon a rich and extensive religious heritage would judge other believers who eat and drink regardless of unclean/clean issues; and how these new believers who are enjoying their freedom would be contemptous of those old fuddy duddies who aren't flexing their new muscles of faith in Christ.
The judging and contempt hasn't stopped amongst Christians today. Music style - contemporary or traditional; Preaching style - expository or topical; ministry strategy - seeker, emergent, or believer-sensitive; church location - urban, suburban, small town or rural; money issues- high quality (building, grounds, equipment, etc) or pragmatic/benevolence; theology - literal or modern.
Who do you judge? Who do you treat with contempt?