These purely formal manipulations seem to skip over some important issues: If the equations of EM are the same as for gravity, then EM- charges should behave li

These purely formal manipulations seem to skip over some important issues: If the equations of EM are the same as for gravity, then EM- charges should behave like mass. But like masses do attract each over, unlike EM-charges which do repel each other. I don't see how they resolve this basic difference between the behavior of masses and charges.