You mean people are united only if the government imposes censorship and limits what can or cannot be said? How does hate speech cause division exactly? It's just a manifestation of peoples thoughts and opinions (however ugly they might be). And maybe division is not necessarily a bad thing. Would you like to be united with people you fundamentally disagree with and help them achieve their goals? Probably not.
Hate speech laws almost always evolve into some form of a censorship, when you no longer can express an opinion even if it's not target at anyone directly. Is publicly stating that e.g. you don't support gay marriage a hate speech? Who is to decide that?
Do you know what racism or hate speech is? Do you like seeing one tribe saying another tribe, do you like seeing a religion saying another religion is not true. I mean things like this and racism is a problem that needs to be straightened out because we have the same position in the eyes of the law and someone who often commits racism is usually quite problematic in life. Differences of opinion are guaranteed in the law, but this does not result in racism against other people's ethnicity, religion and culture who are different from their own.
Hate speech laws are not wrong, it's just that humans themselves cannot differentiate how to interpret racism and differences of opinion. Differences of opinion on things that are positive for human development are not wrong and criticism on this issue is mandatory and the law never restricts someone from having a different opinion, but it is not a sentiment or expressing racism towards other people.
Racists try to make sure that they turn their situation into "facts" and so that would mean that's not racism. I am not American nor have I ever been to America, so I can be objective and tell you about blacks in America for example.
When someone says "they are the ones who commit the most crimes, that's a fact" they do not really tell you why that is true, why they do that, nobody questions the fact that about until 150 years ago they were slaves, about 50 years ago they weren't equal, and about 20-30 years ago FBI (this is official report) murdered successful black people to make sure whites stay powerful, they do not talk about ALL towns burning because they were black oriented and did well. Then they tell you oh they commit crime, of course they do, you left them nothing else.
We always look at the past to compare the superiority of ethnicity, skin color and culture, what's worse we will continue to say our people are the best even though they are nothing. The issue of morality is that we should not need differences to say that our people are superior to other people. Life is cool, safe and peaceful when we can accept each other's differences. The person who committed the crime has its own retribution that will be held accountable through the court decision process and they are on the same side of the law as they should be after it ends.
I don't want to discuss too much about problems that have occurred between tribes, religions and cultures, because I think we have the same position in this world. A life that respects each other and can live side by side is the life that many people are looking for, because we will learn to accept other people and will live side by side without any problems. Crime, racism and morality are just a few problems that have been deliberately developed by a small group of people and when we unite these problems will be solved.