Well, if it were me I'd simply come right out and respond, "Why do you ask?" Then again, I've never been known to be politically correct and seem to put people on their heels with how blunt I am

If the response is something like, "I'm just frustrated and I don't know where to go with my DD/DS ......." then I'd likely fill in and help as much as possible. I don't like to assume I know motives, however, intention plays a huge role in my mind as to how much time I'm willing to invest educating someone. I know what I say is often perceived in a manner that wasn't my intention due to my direct nature, I like to give others the chance to explain their intentions as well.