«فساد الوضع: هو بيان كون العلة غير صالح للحكم»
Fasad al-wad means demonstrating that the proposed cause is unsuitable for the ruling claimed.
The author presents a disputed example about one spouse embracing Islam and a claimed marital consequence. The answer argues that Islam, understood as legally protective of rights, does not serve as the proposed basis for that consequence.
The objection attacks the legal fitness of the alleged cause itself, rather than simply contesting one factual instance.