'...it is the context and the intent that make it sound "spiritless" or insincere, not the phrase itself.'

With respect, I disagree, David: the phrase itself is knackered in the extreme in the spirit department by all the same things that would render a poem so: it is a compromise, vague, evasive, imprecise -- indeed fearful of precision -- artificial, so deliberately abstract as to be meaningless, tied to no particular reality or living tradition, devoid of association, barren, sterile, wimpish. It is a committee-created politically-correct euphemism, bearing the stamp of MiniTruth all over it. Wish me Yuletide Cheer, or Merry Christmas, or Happy Hannukah, or Io! Saturnalia!, or Damn Yer Bloody Eyes, Stevens! -- something real -- but Happy Holiday? It's like saying 'Happy Thursday' or 'Happy 6:00 pm' or 'Happy Nicey-nice', or 'Happy Nothing'. I truly hope it does not spread across the Pacific in our direction. Coastal Patrol alert!