Is white bread really bad for you? If so, how?

Not so much that it's "bad" for you, but it lacks the nutritional benefits of whole grain bread. It's empty calories and a simple carb. If you want to actually get some nutrition out of your bread, switch to whole wheat or whole grain (you can often find either of those for the same price as white bread). The article linked below has info on the differences in white vs whole grain/whole wheat bread.

It lacks grains and has added sugar, of course I don't disparage anyone for eating it especially during this time when money's tight for everyone!

No, our ancestors lived on bread for most of their lives 

No but it’s harder to digest for your body