So why do people make such a deal of deliberately straying from saying “Merry Christmas” or “Happy Holidays” or “Happy Hanukka” and etc?

Seriously, why can’t we just celebrate what respective holiday we like?
Instead of all the mumbo jumbo about “oh, should I say Happy Holidays or Merry Christmas or Happy Hanukka” why not just say “Cheery Holidays!”
(Yeah it’s a bit cheesy but do you have anything better to add? no? then Cheery Holidays to you!)

Cheery Holidays everyone!