I wondered if anyone had explained to them what a handshake was supposed to be--not that all adults are free of the aforementioned problem, but this seemed excessive, perhaps indicating cluelessness.
I don't want to go all Dale Carnegie on you, but he has a point. A handshake is a big first impression, and surely it's not too hard to offer a firm grip, a brief squeeze and release. You can even throw in eye contact for extra credit.
Maybe it's an issue of a child/young adult not feeling confident, but I don't care--act it, at least. Surprisingly, confidence will come and people will give you the benefit of the doubt for starters.
Reach out an touch someone...properly.