Wasn't Locarno in his early twenties? (as most people in their fourth year of university/college are) How much older was Paris? From what I can tell the incident that cost him his commission happened shorty after he graduated. So he was in his early twenties as well, a year or two older than Locarno was when he was expelled. A "kid" as well.
Locarno was a cadet not yet graduated when the group accident resulted in tragedy. Paris had graduated and was serving on board the USS Exeter when his screw up resulted in three deaths.
Just enough difference in age and experience for it to be noteworthy as far as I'm concerned. Plus Locarno and pals simply chose to omit the truth whereas Paris actively "falsified reports."
In a discussion about who is redeemable, I'd say those facts go in Locarno's favour.