Imam Hussain ibn Ali (RA) stood against Yazid ibn Muawiyah due to open manifestations of kufr and fasiq (flagrant disbelief and immorality) that threatened the Deen's foundations, fulfilling the stringent Sunni fiqh conditions for legitimate qiyam (uprising). This was an exceptional case of amr bil ...

No, obedience ("ata'at") to the Hakam e Waqt (ruler or authority of the time) is not unconditionally fard (obligatory) in Islam. It is conditional (mashroot) upon alignment with Quran and Sunnah, strictly limited to ma'ruf (lawful matters). This is the unanimous position of Ahlus Sunnah wal Jama'ah ...