I do agree that Muslim has largely forgot what the Message of Islam is.
But Muslim is not a label that you carry.
Show me a believer and I'll show you he give other's their rights, do salah, pays Zakat etc.
But not ever person who call themseves Muslims, do Salah or pays zakat is a Muslim (you don't have to go very far reading the Quran, to find out that). Quram mentions the way these people get misleaded.
Since when do you have the right to declare takfir?