Written correctly, the sentence should appear as follows:
You can understand better why prefer to is correct and prefer over is not with a little thought. Suppose that you had a choice between two physical objects, each of which has been placed before you. You indicate your preference with the common hand gesture of pointing.
Now, here is the key question: Do you point to your choice? Or do you point over your choice? Clearly, you point to your choice. And that’s why prefer to is correct in written English and prefer over is not. When you think about the functionality of the words, prefer over just doesn’t make any sense.
So always remember to prefer to, not over. Then you can prefer more effective writing to less effective writing.