In the article, they were represented as evil exploiters of children.

represented 是动词 represent 的过去分词形式，在句中表示被动。represent 由前缀 re-（表示"再次"）和 present（呈现）组成，本义是"再次呈现"，引申为"代表、描绘、表现"。 在这里 represented as 表示"被描绘成/被表现为"某种形象。