Georgia law was probably specifically crafted to make as much underage sex illegal as possible so as to discourage it, so "leniency and understanding" would be in defiance of the spirit of law as well as the letter. Not that I'm condoning the decision, of course.
The national US law is actually quite reasonable. It says that statutory rape is sex, even consensual sex, between one person below the age of 16 and another person who is both over the age of 16 and at least four years older than the first person. Thus, in most states, this would have been fine, and it still would have been fine if he was 18 (though not if he was 19). However, some states have stricter laws than the national law, mostly in the South. In some cases, the age of consent is raised to 17 or 18; in other cases the four-years exemption is tossed out the window (which, IMO, is absurd). Georgia apparently lacks the 4-year exemption.