Even in doing good, volunteering and donating to charitable causes, it's such an act. A) Statistically, special occasions seem to be the only time people really think of anything like that; and B) charitable causes are in much more need at other times of the year. Which says, to me, that people only do it to satisfy their own sense of guilt.
It's also a bit disturbing to see huge case-switch statements of different holiday greetings trying to exhaustively enumerate every possible one for whatever could be celebrated by anyone on the planet. There's usually even a default value. There's a difference between trying to include everyone and getting ridiculous about it.
A Hungry Ghost is a soul with an insatiable appetite for attention, stimulation, wealth and benefit, whether or not it's justified or deserved. They are materially and emotionally greedy. I'm not sure if it's worse that people act like such Hungry Ghosts at this time of year or that people feed the Hungry Ghost phenomenon.
What exactly does it matter that you are greeted by the holiday you don't celebrate?
Whether it's "Happy Hanukkah" or "here, I'll help you with the groceries", they're just noises. The meaning behind the noise is much more important. I'm happy that someone thought of me at whatever time they did and expressed as much.
I say again:
I'm just happy that someone thought of me at whatever time they did and expressed as much.