Because he is the one who brought bitcoin to life. And i really think that there would be not much resistance against what he claims to be right. He is simply so very much trusted.
Only his words would be listened to and considered. You've seemingly totally missed the point of the whole anonymous act.
Bitcoin was designed to be protected from the influence of charismatic leaders, even if their name is Gavin Andresen, Barack Obama, or Satoshi Nakamoto. Nearly everyone has to agree on a change, and they have to do it without being forced or pressured into it. By doing a fork in this way, these developers are violating the "original vision" they claim to honour.