The short answer is yes. I think it simply makes perfect sense that employees of FanDuel should be banned from playing the popular fan sports game. The ban came about as a result of one employee who apparently won $350,000 playing, and after the results of an internal probe which suggested that the employee may have gotten his winnings due to some inside knowledge other players outside of FanDuel were not privy to.
Whenever there is the possibility of someone knowing something, rules must be in place where money is to potentially be gained from it to curb that. Pardon the pun, but it's a matter of gaming the system. It's fine to make money when you are doing it honestly and fairly. And let's not forget that the winnings at FanDuel are from monies paid by other players. So playing with knowledge that other players do not have is essentially stealing.
I think the ban is fair, and is a good thing.