People believe that copying is wrong because it is unethical. Top student and dumb students will get equal marks when they copy and that is injustice. Weak student will not study when he gets chance to copy.
Now I am going to present a completely different perspective here. Copying builds dependence. We will not study on our own and we become dependent on others. Sometimes, we try to get conformation from others even though we know the answer. This reduces the confidence levels and damages solitude. We get trapped into new relations just to take and give help. Such relations are toxic and full of expectations.