Not everyone who criticises Mufti Taqi Usmani is the enemy of Islam...they might be on the truth and the Mufti might be wrong. My understanding is that the Mufti allows Islamic Banking intending to make it a step towards true halal...for he admits that it is not really halal now. So his intentions are noble, however the criticisers are saying this is not a step towards halal rather it is a step towards subverting the halal and making the haram into acceptable or 'Islamic'.