If there is a reason/s you don't currently date, do you tell them the truth? Does it depend of who the asker is to you? Will you tell me/us?
My answer: I do whatever I can to shut down the conversation. To me the first question is conversational, the second is downright rude especially as I only seem to get asked this by total strangers. I don't ask people how their marriage is going, do I?
If I have to respond politely, I tend to make a joke about how I'm a freak magnet and how only crazy people find me attractive. This is true. The parts I don't mention are that I work stupidly long hours (with women and gay men only - so I neve meet guys at work), have major self esteem issues, hate clubs and bars because I'm secretly and introvert and I have intimacy issues. Add in the 'taller than most guys' factor and you have yourself a winner ticket for being long term single.
Also, OT but not really.