As mentioned, nobody likes it - not them, not us - and yes, it probably is insincere because it's forced upon.
Having said that, I feel it does serve a purpose in at least giving everyone a chance to meet each other. At the very least, it will give them a "human face" if you will, for who is on the other side of the locked door. We say "call us anytime you see anything unusual" and we try to set the tone of open communication - but without a face-to-face meet and greet beforehand I think it will actually hinder communication and put a even larger gap between us and them.
Perhaps just a introduction in the briefing room, or near the couches would be better than the awkward and insincere handshaking ritual. But before we eliminate the handshake, we need SOMETHING to replace it. Everybody already goes about doing their own thing as soon as we get to the aircraft, and in some cases we don't see them again for the rest of the flight/duty - the handshake at least gives them a chance to see who is flying them and for us to "set the tone", and maybe even a sense of unity/team (rare, but I've seen some captains work miracles)