Josai and CS, the Damian skills that his back story told was a list of mentor Talia forced on Damian that made him able to drive at the age of 5, write a dissertation at the age of 8, and as a Robin, moved his liver to a side for a bit so Dr. Hurt didn't stab it.

It's ridiculous, plain and simple, but it's not more ridiculous than Batman solving and making anything by saying "I'm Batman", building a Batcave on the moon, and climbing out of a jet engine after being stabbed in the gut and starved for seven days.

It's a comic book thing, and in both Damian and Bruce's case, they became more a running gag than anything. If you take it seriously, then yeah, it's a Sue. If you don't, and I don't think you're supposed to, it's just a gag.