It is as if the writer is comparing and contrasting (for example) footbinding to corsetry, instead of corsetry and footbinding to each other.
Write only about the comparable and contrastable elements of each idea.
The introduction to your compare & contrast essay will be a summarized teaser of what you will be discussing going forward.
There are some key points to mention herein which will give your compare contrast essay introduction the angle it needs to fit properly into this type of essay.
This structure focuses on the comparison and contrast instead of on the two ideas (e.g., corsetry and footbinding) being compared and contrasted. If you begin with the comparison, then the contrast will get emphasis - the logical movement is from thinking about similarities to thinking about differences.
If you begin by contrasting the ideas (and then move toward a comparison), the similarities get emphasis. Writers might compare and contrast ideas by treating one idea thoroughly before taking up the second one.
This method is probably the one most students try first, but many evolve past it into something more flexible.
A quick outline that treats first corsets and then footbinding shows one way that such a paper might be structured.
Once you understand these principles, you will be better at forming the introduction paragraph properly.
First of all, the writer of these essays must realize that there is a huge difference between comparing things and contrasting them.