When 'Salafis' and Gibril Haddad does it (because it's directed against our akaabir) it is unacceptable. When Deobandis do it, it is acceptable, propagated, and defended: "Such and such Mufti Saheb is a great faaqih, zaahid, IMAM! He has done so much for the Ummah! How dare anyone criticize his foul language that we spend a lot of time criticizing Ahmed Raza Khan and everyone else for! What's a double standard?"
Very true. Everything is fine till it fits in their world view. Their so called principles are just a party line.