There is nothing wrong with that call being made. Legitimate penalties can and do get accompanied by legitimate embellishment and the thought process of the diver can almost be seen by the way the embellishment is made. The player makes a spectacle of himself to make sure the ref didn't miss the original infraction. Each is actually a separate incident with it's own necessary penalty.
The Markov one tonight wasn't a crazy dive at all, like Kesler or D. Brown would attempt, he still went down easier than half the bambi legged skaters at drop-in hockey would. He is a professional who has been through that same scenario likely thousands of times in his career, he knows how to take that little shot to the back without falling down. Guys with good awareness like Markov know when the player is standing behind him and what do guys do behind your back in hockey? They give you a little shot, almost every time. Better make sure the ref notices... dive. The refs are very aware of what just happened in that routine exchange and the call is made.
I don't think Markov is one of those notorious, dirty divers by any means. I think he's a fairly respectable player, but every player does it at some point. If a player can't handle that minuscule level of expected contact without honestly falling over then pro hockey is not for them.
The rules aren't always perfect and the refs sure don't get every call right but they have been exploited for so long by unscrupulous divers on plays that pros are more than capable of handling. When that happens the rules tighten up in their application and softies like this get called as a result. Better grab a beer and get used to it because the double penalty on these exchanges aren't about to go away.