That's true of Tor entrance nodes too. The key is to not let the first node in the chain know _what_ you're sending, and not let the last node in the chain know _who_ is sending it.

This is the exact problem solved by onion-routing. The first node is called "Guard" for a reason, it can directly monitor all incoming connection to the network, but if onion-routing is used and the system is properly designed, it usually doesn't matter. The only information revealed is the fact that someone has connected.