That seems like it is incorrect. Unless something changed and I wasn't aware of it, it was understood that placing a copy of Ninja is the same as playing that Ninja, just with non-Unique. This action is a put in play, not a deployment. The only thing to be met is the Sacrifice Requirement.
However, it could be that Reinforcements don't work that way when you place a copy of them in play. Since Reinforcements are technically a non-deployment put in play, it can be understood that you have to meet the Entrance Cost and Hand Cost and Sacrifice Requirement just like when playing a regular Reinforcement Ninja.