The fashionable criticism of the campaign is revealed as the shallow stuff it often is.

本句有两个语言点：

1. reveal...as... 把...揭露为/披露为...，被动式：be revealed as... 被揭露为/披露为。

2. it often is 是定语从句，先行词是stuff，省略了关系代词 that，关系代词在从句中作表语时可以省略。等于：the shallow stuff that it often is.

【等于】对此次竞选活动的流行批评被揭露为通常是肤浅的东西。