Cafe au Lait, and the consequences thereof

I drink my coffee "cafe au lait" style, which means I fill my mug halfway with milk, microwave it until it's hot, and then top it off with 1/2 cup of coffee. (Yes, I'm sure if I was drinking coffee on the banks of the Seine, that's not EXACTLY how Jean-Pierre would do it, but I am, after all, an American, so ... pffft!) This is the ONLY way I can drink coffee at work, because, like most workplaces in these United States, we have a piece of crap Bunn coffeemaker, which burns the bejeebers out of the coffee, rendering it horrible. So every day I carry a little pint-sized container with milk in it to work. I make 4 cups of cafe au lait during the am. I figure this is a pretty good thing, because:

1. I need my coffee, so I will drink it and don't tell me about decaf!
2. This way, I'm actually only drinking 2 cups of coffee, since half of what I'm drinking is milk
3. I'm getting a pint of milk, which is a calcium boon, plus has protein and vitamins A & D
4. I recently switched from 1% milk to 1/2% milk, which only has 1 gram of fat, so it's pretty darn healthy (I can't remember if it's 90 cals or 100 cals, but it's pretty good health-wise)

Great, you're saying. Bully for you, Big Seester. Why should I care?

EXCELLENT question. So explain to me why two of my co-workers decided today to give me the third degree about my coffee drinking habits.

Woman 1: Do you drink ALL THAT MILK every day?
Me (slightly taken aback, but because I haven't had my coffee yet, playing along): Yes.
Woman 1: Why?
Me: (I explain generally how I take my coffee.)
Woman 2: You drink FOUR CUPS OF COFFEE EVERY DAY?
Me (now officially getting irritated): Um, no - I drink 2 cups of coffee, and 2 cups of milk.
Woman 1: Well, if that's how you LIKE to do it...
Me: (makes a hasty exit from the kitchen with my cafe au lait before I say something I will regret)

Now, I have pondered this all morning. What in the name of mike was going on there? I mean, first of all, I have worked here for a while now, so it's not like this is a new thing. Switching to 1/2% milk is a new thing, but you can't tell what kind of milk it is just by looking at it. So there's that. Then there's the whole, oh I don't know, IT'S NONE OF THEIR BUSINESS HOW I DRINK MY COFFEE thing. And here's the part that tees me off so much: even though I have definite opinions about food and so forth, I don't spew them onto other people (except of course here, and to family members and close friends). I would never dream of looking at Woman 1 and saying, "I can't believe you are putting that powdered artificial creamer in your coffee - it's not even FOOD!" (even though it ISN'T food, and the concept that anyone in this day and age would use that crap appalls me). I wouldn't even dream of saying to Woman 2, as she heads downstairs to take another smoke break, "I cannot believe you're going to smoke another cigarette!" (even though it is unquestionably bad for her, and she hacks so loud you can hear it across our entire floor). My feeling is, "It is none of my business if these women want to make choices I disagree with. They make the choices they see fit to, and I make the choices I see fit to, and that's that. We're all grown-ups here."

So what gives? Will someone explain it to me, PLEASE?! Because I don't understand! I don't get why cafe au lait would even BE a bad choice, much less one so bad that other people feel the need to provide their input...