Life is unfair. That's fact. Everyone has different stats. Social status, looks level, family condition, intelligence level, talents, etc.
Yes most suffering on the planet is caused by humans. Just do a body count of man made disasters like totalitarian governments, wars, etc. Vs death by natural disasters. Even if you don't even factor natural disasters caused by human activity and say it's all 100% natural.
Caused by the human ego. Yes. The root of selfishness yes.
But at the end of the day, look at the mirror. You're human and you have ego too. That's the cross you must carry or the jihad you must fight against however you wanna see it.
The best you can do is make the most of it. Strategize for your survival and thriving. And how to help others as well. You will reap what you sow trust me.
And finally, don't take life too seriously. Find the humor in it. 