是的，不宜说受all修饰的先行词必须后接that引导的定语从句，只能说：当先行词受 all 修饰时，其后的定语从句通常（不是必须）用that来引导。如以下例句均来自词典或语法著作：

These are all things which can be overcome. 这些都是可以克服的东西。

I cut down all the trees which were evergreen. 我砍倒了所有的常青树。

I pull up all the flowers which looked like weeds. 我把所有看起来像杂草的花都给拔掉了。

The cat licked up all the milk which had overflowed onto the floor. 猫舔光了溢到地上的牛奶。

First of all, he wrote out a long list of all the foods which were forbidden. 首先，他开列了一张长长的单子，上面列了所以禁吃的食物。