Is it sexism?

There's a subtle, invisible line you're not supposed to cross in interviews about your potential employee's personal life, at least in american interviews, that is definitely stepped over here.
At almost every interview I've been at so far in Japan, the same questions in the same order...they go down the resume and ask questions about all the information on it. So normally they start off with
"tell us about your programming experience.."
it then gets a little more personal, with questions like
"So, how good is your japanese? " which is fine, I now have at least some certification, even though I usually have to explain what it means.

Next is slightly more personal, but still work related.
"how long will your commute be? Is that going to be alright for you?" Well, you know, hour long train rides suck, but minute for mintute it's probably better than being stuck in traffic.

...and then there is a little check box on these resume forms here that says if you're married or not, which generally leads to the question:
"I see you're married. Is there a particular time you need to be home at?"

I never know how to answer that.
Yesterday I tried the tact of saying:
"Um, I don't have a curfew, if that's what you're asking..."
The interview guy exchanged glances with my company's contract coordinator, who was also in the interviewing room, and together they sort of hummed and hawed.

I felt myself starting to brew with a slightly unwarrented anger.
"WHAT? go on and SAY it! You mean, 'Don't you need to GO HOME and COOK YOUR HUSBAND DINNER?' because you're a WOMAN?!"
the little feminist in the back of my head was standing on her soapbox with a megaphone, causing the drunken crowd in my mind to yell"MrRRRYYYEAHYOU TELLEM!!"

As I tried my best not to burn smoking holes into the interviewer's shirt with my glaring eyes of vengeance, the contract coordinator stepped in with a quick "well her husband works at a bank on a shift schedule, he often has the late shift".
This caused the interviewer to look a bit relieved, so it looked like the day had been saved.

Still, did he really need to say that? Did he really just say "she's not a bad wife for being willing to work late, her husband has the late shift so it's ok if she doesn't make him dinner?"
I hate to sound mean, but he's a big boy who can use a frying pan all by himself now!

Maybe I'm overanalyzing this.