This thread has veered into crazy racism, but I wanted to address this point. In the US, we don’t have a problem with the lack of severity of punishment for most crime. We have a lack of consistency of punishment. If you want to cut down on sucker punches like this, you have to criminally punish violence. Every act of violence, every time. When someone hits someone else, outside the context of express mutual agreement (MMA, boxing, etc) they should be held criminally liable. No need for a long sentence, just something to let them know that they cannot be antisocial and get away with it in a civil society.
Right now, we all know that if two dudes get into an argument at a bar and a few punches are thrown, most likely all that will happen is they get kicked out. But they could get arrested. Or maybe it gets broken up and nothing at all happens. One thing is for sure, the two dudes aren’t considering the length of a potential prison sentence for battery before they throw blows. They are, however, probably aware - at least subconsciously - that bar fights are fairly acceptable and the fight probably won’t have any ramifications beyond the end of that night.
So there is very little incentive in that situation not to get violent if you believe you can beat up the other guy. And if someone challenges you to a bar fight, you look scared and weak if you don’t engage. Society would be a better place if everyone at the bar understood that any violence would almost certainly result in arrests and punishment that have an adverse impact far beyond simply being asked to leave or getting a black eye.