I'd say for two reasons. Firstly, the article suggests that immigrants were controlled (whites and blacks compared) for so it appears this poster is commenting

I'd say for two reasons. Firstly, the article suggests that immigrants were controlled (whites and blacks compared) for so it appears this poster is commenting on something without even reading it, and secondly, the style of the comment makes it clear the commenter is a smug prick with a belief in their own smartness beyond their actual ability - nobody likes a smug prick who doesn't even read the article.