^ after imam ahmed bin hanbal???? imam ahmed bin hanbal is the last of the four great imams, u mean to say that before him the other imams did not consider Ali (ra) to be one of the khulafa-e-rashideen????
indeed , the other imams abu hanifa, shafai etc did hold Ali in very high regard but could not publicly support him as that meant imprisonment and as ahle sunnah was the official faith of the empire that meant Ali could not be included amongst the pious caliphs as it was not approved by the govt.At thattime anyone having sympathies for ALi was called a "rafidha" much the same way present day pious muslims are called extremists.having said that extremists shia sects did start forming after the revolt of amir mukhtar.
abu hanifa did go to prison for supporting zayd b ali and nafs azakiyah 2 descendents of ALi against ummayyads and abbassids
after death of umar b abdul aziz the practice of cursing ALi was restarted.
it was banned again under mamun the abbassid caliph