Well, unless you're positing that DSC is actually set in the Kelvin-verse, the Kelvin incident never happened in this reality. Kirk was born on Earth, the Enterprise has been out there for over a decade (rather than being under construction), Starfleet has not built the Vengeance or anything like it, and the planet Vulcan has a long and healthy life ahead of it. This is (so we're told) the universe of Shatner's Trek.
All that said, I still think it's ridiculous to imagine that the Klingons (especially as depicted here, Balkanized and without any overarching strategy beyond opportunistic raids) would have a snowball's chance of defeating the Federation, and frankly the story to date hasn't ever made the threat seem that significant.
And yeah, I'll be severely disappointed if Georgiou isn't held accountable for her actions. (Although I'm sure we're likelier to see some form of "poetic justice," knowing these writers, rather than anything so pedestrian as an actual legal process.)