In the (software/web) start-up culture, technical means writing code. If someone says "I'm creating a fitness app, yeah I'm technical" you expect them to mean "I can code" rather than "I know how to use CAD". Your argument applies in many contexts, but not this one.
Yup, I kind of acknowledged that already, what you say is true of course. Yet in my environment I can still imagine software scenarios where I can say "you need a technical guy for this" to my friends and mean a non-programmer or a special type of programmer. I say no harm in being precise if it costs nothing.
If you are pitching to a potential investor about this idea for an app, and they ask you "So are you technical?" what they mean is "Are you a technical (co-)founder?" as in "Are you the guy who will build/design the prototype/app to a working level before we pour enough money in for you to actually hire decent coders?" When you say yes, but later reveal you don't know how to code but you studied nutrition, they are going to get annoyed.
Once again, it's context. In many worlds technical means other things, but to North American VCs looking at software/apps/etc, it means you know how to get the app/site/whatever running. Since we're talking about the startup world, I really can't see how a potential investor would see it as anything less than deceptive if you said "yeah I'm technical" and then revealed you don't have the capabilities to implement your idea.
