What you mentioned is ‘Islamic principle’ but these dheet Fitna-gar people are not even proper Muslims. They are quacks claiming to be guardian of Islam.
On the other hand, in Islam, state has nothing to do with individual’s personal beliefs and deeds (hence blasphemy law is unislamic … imposed in subcontinent by British to control tension between emotionally charged-up population … something Zia modified to make it worse and his spiritual son Nawaz introduced into it capital punishment). State can only interfere in mamlaat (dealings of people with each other).