Indeed, no one died directly on the bus, but the degree to which he kicked their asses was kind of insane imo. And this only because he was a trained killer. I believe even the law judges you differently if you're highly trained and do that sort of damage to civilians.
And as I said, him wanting them to get on the bus and his general behavior did feel to me like he was out for blood.
So when someone dies because of his bloodlust and him not wanting to temper his obviously high skills in combat, it feels strange for him to claim ignorance. Technically, I believe he could've knocked them all out very fast, swift and causing as little bodily damage as possible.
All of this put together made it a bit hard for me to empathize with his position when he then behaves like they came for his family out of nowhere, when his own actions caused that. Indeed, there was no going back from what he did, but if he would at least accept his responsability in all of this I could have empathized with him more. But no, his next action was to go and burn their hole money operation just out of spite. That does not seem like a person wanting to keep his family safe. By taking on the whole of the Russian Mob (which is effectively what he did when he burnt all of their money). Does that seem like someone who cares for his family, or was it all just an assault on his ego, that they came to his house?
Sure, it all made for some fun situations. But the core of the motivation was a bit weak imo. At least compared to how John Wick did it (at least from the little I watched of the first John Wick) where the whole trigger is some bad guys hurting his wife's dog? If I remember correctly. Anyway, that trigger felt a lot more innocent and you could more easily get behind.
Anyway, I feel I've spent way too much debating this movie, and it's not worth it. But these are my 2 cents on the plot.