It’s not offensive. I’ve said Happy Hanukkah and Merry Christmas to customers and friends through the years. Also when I lived in Indonesia, which is 90% Muslim, I wasn’t offended to be greeted with an Islamic greeting. Nice people of good will can go with the flow and exchange specific holiday greetings.
Now the video above may be a bit preachy, but he’s right. As they say, “Gratitude is riches. Complaint is poverty.”