Dont get me wrong, Tajikistan is a capital D dictatorship. With pictures of the president on every public building and daily propaganda prodcasts from megaphones installed at public squares. Its also not the first time the government banned certain traditions (such as a way to celebrate weddings).
They are banning the symptom instead of the cause. Instead of banning preachers of foreign schools of Islam they are banning something that is central to those preachings.
I agree, banning religious expression is generally a bad thing, I am just happy they are fighting to keep radical Islam out of the country. For reference, Tajiks are the second largest ethnic group in Afghanistan (~25% of the population) so there is bound to be cultural exchange between the countries. a And Tajikistan is very afraid of the Taliban getting any support in Tajikistan. And the first step of that support is through religious radicalization.