Look folks, you don't have to go on a purge.
Cracking down option is just that, a crack down on the sects that acted above thier mandate, not a purge like the rip them out option.
Furthermore, purity itself is not a bad trait, could be a greatly beneficial one depending on where it develops, and how intricate the theology is.
And got that to happen puritanical doctrine has to become unfashionable. Puritanism at its core is a reductionist theology that disdains theological development and complexity. Naturally, doing a purge will reinforce certain parts of thier message, if not turn them to martyrs outright.
As such, the best way to deal with it, is to shift the focus of theology in a different direction, by emphasising different aspects of society.
Such as commerce, opulence, foreign involvement, political vibrancy... Etc.
These subtle forces do wonders in shifting doctrinal focus.