TL;DR: Although a lot of people with a .edu address are broke, we can't make sure that everyone with a .edu address is broke. And there are surely people somewhere in the world poorer than anyone with a .edu address. So nobody gets a discount.
"Because I don't want to." would be more frank and straightforward than all those made up arguments.
"Because I don't want to." would be more frank and straightforward than all those made up arguments.