I don't find the 'how are you?' particularly odd or annoying, although completely not necessary. I do find the 'Happy Valentine's Day' strange. It's an observance about close relationships, particularly romantic ones. Sounds odd to be 'wished' it by a complete stranger who knows nothing about my love life.
Well...when I was a kid, every kid in the class got a valentine. And there are people for whom it's about hanging a flag on the front of their house, leaving chocolate hearts on everyone's desk at work...
I wouldn't read that much into it.
(And I'm someone who would rather not get into too much social chitchat at work, because it's a professional interaction, and there are ways to treat someone like a person without the meaningless call-and-response.)