Why ? If you wrap the message into multiple layers of encryption (TOR style) that needs to go into multiple nodes, and if alongside the next encrypted layer you have a date the nodes agrees to wait to pass the message to another node, that would work, no ?
Even with some corrupted nodes, the message would still be secret, the only issue would be if the last nodes are corrupted : your message would be distributed too soon. But with enough layers and enough nodes to go through, you could mitigate this risk.
The network could even detect corrupted nodes if other nodes received the message too soon.
Because each node generates its own key pair and when encrypting a message you choose a random route and you use the keys of the nodes of your route to encrypt each layer.
What the person you're replying to is talking about is a Sybil attack. You pick random nodes, yes, but what if the list of nodes to pick randomly from is 99.5% the attacker? This is a real world attack that has been used against Tor, for example.
Even with some corrupted nodes, the message would still be secret, the only issue would be if the last nodes are corrupted : your message would be distributed too soon. But with enough layers and enough nodes to go through, you could mitigate this risk.
The network could even detect corrupted nodes if other nodes received the message too soon.