I wouldn't blame that on people, most people ARE fundamentally peaceful, rather, it's the (as I like to call it) "different interests" causing all these troubles.

Everyone is different in their personalities and their means to achieve what they want, so eventually someone may have conflict with you and makes you feel bad. But I've live long enough to realize all of those conflicts are just part of (good old) living, you can hate someone while still find a way to corporate efficiently to make both of you happy.

However, the story of The Expanse told me that, as long as we as human beings refuse to learn how to resolve or moderate our conflicts, we'll bring it along no matter where we go, different country, different continent, different planet or even different galaxy etc. We'll find a way to differentiate each other and attack.

That's why it's sometimes good to go back to the fundamentals, think what do we want to fill our lives with? Hope or hate?