Yes, you are right.
Same thing too with Valentine Day.
Got answer on Discord that it's not because saying "Merry Christmas" is offensive.
Christmas, Hanukah, Kwanza, and Boxing Day all happen around the same time
and since they're all in such close correlation to one another,
most companies (including SEGA) just put all under one banner as "Happy Holidays".
I find it interchangable really, but the thing is (and I'm sorry Jews, Vikings, Africans and all other cultures for alternate winter holidays out there) Christmas is the #1 holiday of December, probably the most popular of all known holidays.
The reason why Christmas is so popular is because not only did the ancient Christians knew how to market it (adopting pre-existing winter holidays and enforcing it on others) but it is also a marketable holiday itself due to gift-givings and the material side of Christmas, thus why it has become so popular amongst corporations.
It's like how the British feel when American English is the true authority of the English language now. It's just something we brits have to put up with and accept that the world prefers "Simplified English" over "Traditional English", American TV shows in UK aren't dubbed or edited for british audience and usually foreign language TV or Movies usually turn to America to dub their shows than Britain because America is the go-to for that sort of thing by now.
Because of that it's why I think Christianity as well as those with yule logs up their arses should be leniant on promotional events that dare use the word "Merry Christmas". Especially if the use of "Happy Holidays" is for promotional events that cater specifically for Christmas. So if Sonic Boom: Speed Battle or that colourful Vocaloid phone game ever get a "Happy Holidays" event, don't hold your breath it will involve a menorah or a kinara, it'll likely have someone dressed as Santa Claus or an elf.
(And yes, I know as a brit I use "Holiday" to refer to Easter, Valentines, Halloween and Christmas when to an englishman it means the same as what Americans call "vacation", it's just I don't know the propper british word to refer to Easter, Valentines, Halloween and Christmas. To call them "celebrations" is more of what you call a party and "observance" is like something you look at than get involved in due to traditions.)