While younger children should not be on platforms where 13 is the minimum age, it is neither practical nor desirable to imagine a world in which teenagers are prevented from accessing the platforms and messaging systems that the adults around them use to organise their lives.
虽然年龄较小的儿童不应使用最低年龄要求为 13 岁的平台,但设想一个禁止青少年访问身边成年人用来安排日常生活的平台和消息系统的世界,既不现实,也不可取。
句首的“it”本身没有具体指代内容,而是占据主语位置,使句子保持自然语序;真正的主语是后置的不定式“to imagine a world...”。句子可改写为“To imagine a world ... is neither practical nor desirable.”,但原句把较长的真正主语后置,因此属于不定式作真正主语的形式主语结构。