You missed the point. He just listed some days, I have no idea if those are the "right" days for each of those religions (you probably would have arguments about that anyway), and there's no real definition of which religions you'd need to include. So basically a mess, easily avoided by not including any specifically religious holidays. Include federal holidays only.
That's one option. Or, we can just not be dicks about it and let people have their holidays.
I'm guessing you don't live in a very diverse area. Conservatives tend not to anyway.
Around me people celebrate Christian holidays, including the Catholic oriented ones, as well as Rosh Hashanah
Yom Kippur, Ramadan, Diwali and Chinese new year. Eid? Maybe. I notice Ramadan more as people are fasting.
Is it something to get upset over? No. Why should anyone? It's just silly.
You can enjoy the holidays yourself too. I'll happily go out with friends, enjoy the special food, and have a good time.
I'm atheist and I don't care. I don't buy into the voodoo, but it's a nice holiday anyway and it makes people happy.