How were they non autocratic? It was him imposing them, because he was the only one who had power, and that didn't change until the 1905 revolution briefly, and really February 1917.

Alexander II might have had some liberal tendencies ( freeing the serfs could be seen as just a modernising effort), but his son and grandson, Alexander III and Nicholas II, were reactionary autocrats to the fullest extent possible.

Ever since the Enlightenment, the Enlightened Despot was something Russian Tsars saw themselves as. It was their destiny to rule as Fathers of their people, but with an iron fist. Dissent was punished with exile or execution.