“Happy Holiday” for Thanksgiving?

So I went to a few stores today to pick up miscellaneous things (like eyeglass cleaner at Sears where they wouldn't let me buy it because nobody was in Optical) and people at stores said "Have a happy holiday!" So is Thanksgiving so offensive now to some people group or something where it has to be referred to as "holiday?" Ok, I don't get that and frankly, I don't want to.

So I wish everyone a happy THANKSGIVING!

-T