If you have a node that is receiving the data then you know what is fake (because you disregard it) and what is real (because you continue to relay it)
Good thing we were talking about protecting against traffic analysis by a passive third party attacker instead of a peer.
It is still a valid point and something that needs to be overcome in order to prevent your identity from being discovered by an attacker. If you only solve for one problem while ignoring others you are doing nothing to protect yourself.