You don't have kids?!?!

I hate this question/accusation.
For the past 14 years, I've worked in Health Care. April 2013, I quit to pursue writing - both grants and novels. A few months ago I got freaked and decided to sign up for an agency, where I could go into different hospitals and work, keeping my skills up and making sure I'd always have a job. Last night was my first night back into the foray.
Everyone always wants to know about the new person, doesn't matter if you'll ever see one another again, you always have to ask the routine questions. Are you married, do you have kids, why do you work agency, etc. I was taking a break last night when this guy came in and asked if I had kids.
"Nope. I have cats," I replied.
"Are you going to have kids?" He inquired further.
"Nope, I'm good." I answered, curtly.
"How come?" He pressed.
"I don't want kids." I lied to us both. Someday, I'll actually believe it to my core.
"Are you married?" He asked with increased curiosity.
"Yep. Been married for over 9 years now." I responded with a smile, knowing where this conversation was headed. It always goes down this path.
"And he's okay with you not having children?!" The disgusted shock was palpable.
"Yep," my curt tone was back. Any sane person would recognize the tone and end the conversation.
"So you're not having kids?"
"Nope."
"And you're both okay with that?"
"Yep."
"He doesn't want kids?"
"Nope."
I won't bore you with the remaining repetitive questions, but this conversation went on for a good 7 minutes. Normally, just to end the lengthy series of inquiries, I just tell the truth. I wanted kids, I'd love to be a mom, but I can't. I had cervical cancer at 18 and giving birth was taken from me. I can have miscarriages, which are fun (not), but cannot carry to term. This revelation usually completely changes the tone of the conversation. Only once have I had someone ask me why my husband hasn't left me because I can't provide him kids.
That was the only time I was left absolutely speechless.
I can't tell you why I didn't say that, except to say that I'm really tired of telling people things that are really none of their business.
I know what you're thinking, "What's the point of this, Jean?"
Here it is: Why is having kids so important? Since I've accepted not being a mom, I've been content with that decision. Why is that wrong? Why can't my family just consist of me, my husband, and our cats? Why does having people children create a "family"? I don't understand it. Why am I deemed defective simply because I don't have people children? What's wrong with not wanting kids?
I don't treat you badly because you chose to have kids that run in front of my car, spill things on me when I'm shopping, or scream in my ear because they want a toy and you haven't taught them that tantrums are unacceptable. I don't send you dirty looks in restaurants, look at you sympathetically when you tell me you have a bunch of kids, or ask you if you'd like to give them up for adoption when you talk about how sometimes you'd like to be without the kids.
I understand that having, or not having children, is a personal choice. I'm always shocked and amazed at the judgement I receive from others in today's society. I naïvely think that we're an enlightened and accepting generation, and am constantly reminded that we're not.