Bais din forced people to keep halacha well after the churban. We force ad shetaytzei nafsho to be mekayam a deoraysoh and punish with makaa mardus for a derabonon violation, makos for a laav.
Of course halacha was enforced. Something that you thought was pashut in your youth which you discovered was false (like avrohom wearing a streimel) must have made you question everything, to the point of absurdity.