Utterly absurd. The average murderer only serves 7 years, the mostly peaceful arsonists of ANTIFA and BLM don’t even get prosecuted, and the guy gets 25 for hitting an animal. In NYC you don’t even get put in jail for assaulting a cop Eighth amendment says something about prohibiting cruel and unusual punishments.
The problem is you are conflating sentences and time served. Seven years is (or was, haven't kept up with it in a few decades) was the minimum for a life sentence. So the press can get a headline 'killer sentenced to life for murder', but the parole board determines the amount of time served.
And even there, your statement needs some qualifications. The guys getting out after 7 years generally had clean records before going in (and are generally well behaved in prison), and killed a wife or girlfriend who knew how to push their buttons. Someone with priors or with a cold blooded plot or excessive brutality was going to do more.
I think it's OCGA 42-9-45. And they used to have paper worksheets that defense lawyers could go through with their clients when discussing plea deals. It's probably all computerized these days.
Found this online - can't vouch for its accuracy
https://kleinrock-law.com/apps/parole/parole.html