In A Christmas Carol, why does Scrooge say that Fred should not be happy?

In the first chapter, or stave, of Charles Dickens A Christmas Carol, Ebeneezer Scrooge receives a visit from his nephew Fred. Fred has come to invite Scrooge to Christmas dinner. Before Fred can issue an invitation, however, he must first answer to Scrooge's confrontation about whether Fred has any cause to be merry at this time of year. Fred arrives with the shout, "A merry Christmas, uncle! God save you!" Scrooge responds to this...

In the first chapter, or stave, of Charles Dickens A Christmas Carol, Ebeneezer Scrooge receives a visit from his nephew Fred. Fred has come to invite Scrooge to Christmas dinner. Before Fred can issue an invitation, however, he must first answer to Scrooge's confrontation about whether Fred has any cause to be merry at this time of year. Fred arrives with the shout, "A merry Christmas, uncle! God save you!" Scrooge responds to this with his famous catch-phrase, "Bah! Humbug!" Fred then questions whether Scrooge really means to call Christmas a humbug, and this is what opens the door to Scrooge's rant about people who are poor not really having any reason to be merry. Fred points out the flaw in this logic by asking Scrooge how he can be so dismal and morose since he is rich. Scrooge continues his explanation of the faulty logic of being merry while poor, saying that Christmas is "a time for paying bills without money; a time for finding yourself a year older, but not an hour richer; a time for balancing your books and having every item in 'em through a round dozen of months presented dead against you." Fred very eloquently rebuts Scrooge's speech, and Bob Cratchit applauds him from the other room.

Fred is not the only one who Scrooge believes is too poor to be merry. Upon hearing Cratchit applaud Fred's speech, Scrooge scolds him with the threat of being fired. After Fred exchanges season's greetings with Cratchit and departs, Scrooge continues to mutter about the lunacy of being happy while poor. He specifically cannot understand how Cratchit can talk of a merry Christmas while only earning fifteen shillings per week and having a wife and family to support. In Scrooge's view of the world, poor people (a group to which Fred and Cratchit would supposedly belong) have no cause for joy and do not deserve charity. They can go to established facilities such as prisons and workhouses. His feelings about charity for these people are summed up in the statement, "I don't make merry myself at Christmas and I can't afford to make idle people merry."