"Loyalty" in Football is something that you can't meassure at all.
You can point to players like Del Piero and call them loyal, but its pretty easy to be a loyal to a club that's playing at the top.
Do you think players like him, Maldini etc would of stayed at the clubs they were at, if they weren't the clubs they were?
So I don't know really why people look down on "Club Hopping players", firstly some people might just enjoy playing in different cultures/clubs?