It is not about belling the cat or slaying the Dragon. Rather, it is about riding the cat and taming the Dragon.
How easily people get motivated to the highest degree whenever a religious duty is invoked, will always be a powerful tool for those who know how to use the religion.
In this world, in almost every country you will find such laws that are reduced to a mockery of the purpose they were made for. However, people almost never take such laws seriously, and even the law implementing agencies look the other way - unless the law is brought into question by some entity, and that becomes the last day of survival for that particular decree.
For example, in India, smoking in open public parks is illegal, and everyone knows. Never gets implemented.
Per Indian law, congregation of more than 10 people amounts to rioting, but you'll see groups everywhere, everyday - esp in buses/trains.
Tailgating in the States is illegal, and some times even gets implemented, but more often than not, people do follow each other in cars and rarely get arrested.
More apt example would be of that law in the States that stated that Nelson Mandela is a terrorist and is now allowed entry in the country. Not only Americans themselves were aghast when they came to know of it, the statesmen of the US felt totally embarrassed in the international community. See, that ridiculous law was so well ignored, that even the people were ignorant of its existence.
And there's a blasphemy law in India too, which states that making any statement or committing any action that hurts the sentiments of any religious community will lead to arrest. It would literally mean that people are not left with any right to carry out any debates on religion. But it happens everywhere, everyday.
And then we see the blasphemy act in Pakistan's constitution. This too could easily be ignored. But people do get riled up upon desecration of Kuran - only when the offender is weak and smaller in size. When the offender is powerful, the indiscretion is either ignored, or settled with other means. When the offender is weak, the crowd won't settle for anything but blood.
Gutters of Lahore keep getting choked with pages torn straight out of Kuran, but no one says a thing. And no one seemed to have a problem when a cleric himself burned Kuran papers and handed them to a mentally challenged Christian girl (who almost got convicted - if it were not for international pressure).
So you see, it is not about belling the cat. Rather, it is about knowingly allowing oneself to become a deadly tool in the hands of the powerful one.
This sin originates not from the existence of the law, rather from the moral corruption of those who find their guidance in the preachings of their local Dragons. Whether you slay the dragon, bell the cat, the crowd will remain the same.
The source lies in the people, not the Mullahs.