This is a system set up by the founding fathers, people would want to stick with the passed down, original tradition.
It also gives low-population states a say in federal government where higher population states might overwhelm them, if its possible to that is. Plus, in my opinion at least, popular vote is pretty much useless
Explanation:
African Americans came back as liberators
Women worked when the men fought
Japanese Americans were sent to internment camps, wrongfully suspected as potential traitors