That's the pretty obvious interpretation, regardless of what the official explanation might be.

It's really not fair. Nobody is cut from a different cloth. We all would have done what they did. The reason we think we wouldn't is because we take for granted what we know. Even then, we take for granted we think we know better, but they have to deal with poisoned fruit and there's no legal system above them to protect them.

I see a tired old man who is content to live out the rest of his life without using his 'new' power to rock the boat too much. I also get a sense of superiority in his face; not quite a smirk, more like he KNOWS he's removed from the rest of us and he's fine with it. Something more tangible, his hands are definitely bigger in the painting than in real life (look closely at their size relative to their heads). Notably, while the rest of the painting is shades of red, his hands seem to be the only 'clean' part of the piece (other than his face for obvious reasons). Also, the coloring of his uniform(?) and the background are practically identical and, in my opinion, clearly meant to blend into each other; almost like he's trying to disappear into the background himself, which ties back to my first point.

In all honesty, I think the complete domination and blending of red throughout, the slightly enlarged hands that remain entirely clean, and the look of self-satisfaction make a pretty strong argument for representing the blood that was spilt to allow him to become king at all (even if not by his own doing). As for why Charles would allow the creation/public revelation, perhaps he's simply acknowledging that legacy, even if he's probably not willing or able to DO anything substantial to make amends ¯\_(ツ)_/¯