If that's your goal, you should be using a SOCKS proxy. VPNs are designed for an entirely different purpose.
So while there is some truth to your statement, some people do that, their actions make about as much sense as:
Inserting a screw is often the entire purpose of a hammer, at least from a clueless standpoint.
You CAN hammer a screw in, and many people have done it. I have, once. Sometimes it works. But it would be stupid to say that a hammer is broken because it's not very good for inserting screws. It's the wrong tool for the job. If you want to install screws, use a screwdriver. If you want to have traffic for a particular application (such as browsing or BitTorrent) come through a different IP, use a proxy. If you want to securely access a LAN remotely, use a VPN.