Im not a very good technical expert, but I think at the moment there are running 12 Witness-Nodes and they are saving the Network. At the moment they are hosted by developer Tony in the Future it should be de-centralized and you can chose them in your wallet.
So at the moment the Network is not fully decentralized.
This explains why there is no a protection against an eclipse attack, which can be conducted if a naive peer discovery is used (which is the case of Byteball, I noticed this trying to recover byteballs of my friend). In IOTA necessity to talk to people is an anti-Sybil measure. Poor SatoNatomato doesn't understand all these nuances, I suggest to forgive his childishness.