Taʾkīd al-dhamm bi-mā yushbih al-madḥ reverses the mechanism: a phrase appears to open room for praise but reveals still more criticism.
First pattern:
«فلان لا خير فيه إلا أنه يسيء إلى من أحسن إليه»
“There is no good in him, except that he wrongs those who treat him well.”
Second pattern:
«فلان فاسق إلا أنه جاهل»
“He is immoral—except that he is also ignorant.”
In both patterns the promise of an exception heightens the negative effect. The apparent opening toward praise results in stronger censure.