Christmas is also powered by a hefty dose of seasonal nostalgia. We want our own families and friends to experience the magic we had as kids and to relive those times ourselves. Nostalgia is geological as much as anything else and so we naturally attach those memories to the places we grew up.
It may not be that Christmas is ‘worse’ in Japan, just that all your memories of it are associated with home also. If I lived anywhere other than the UK I don’t think Christmas would be the same either. For a month a year the whole country takes on a Victorian theme as that era forms an important part of our national identity. Regional folk carols are sung in pubs up and down the land as highly localised tradition takes hold. It’s all rather wonderful :)