[...]
Well, laws of nature are tough, but I personally think that most atrocities are perpetrated by humans.
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Initially, I would like to point out that we can’t measure everything by the same yardstick. I am well aware [no comma] that there are many humans who make the world a better place. The big authors and musicians are brilliant and invite you to dream and to believe in love or to think about big philosophical questions. What is more, there are many charities and volunteers trying to help humans and animals in need. Also, there are a lot of people who try to live environmentally conscious and they attempt to cause as little damage as possible. Unfortunately, I cannot help feeling [although "I cannot help but feel" is also correct] that this is not the majority. When you dip into the past, there have always been terrible crimes against humanity, but is there really a difference between then and now? Thousands of humans suffer from famine or political crises. If you ask me, theoretically there is a solution: balance. There should not be such a big divide between the rich and the poor, yet all we care about are first-world problems. ["The rich and the poor" is something of an established phrase and more commonly said in that order.] In my opinion, human activities surely do not make the world a better place. Money makes the world go round. Egoism and fear are also a major problem.* We are lucky to live in one of the best-supplied countries in the world, and we cannot complain about anything. However, we pay a high price for it: exploitation of other people, pollution, and cruelty towards animals. Only residents of the First World are lucky.
*"The crux of the matter" is a phrase that means the most important, critical, or central point of an issue. So you would not say "
a crux of the matter," but rather "
the crux of the matter," and only if you actually mean it is the single most critical point.
Your English is wonderful: grammar, vocabulary, and sentence structure are all very good. Most of the mistakes I see here are only minor things that you should be able to improve on easily as long as you keep practicing. So, the best advice I have is just that: practice, practice, practice.
I don't notice any major issues I would suggest you work on, but two small things are that you do use "but" a lot, like you said, and you often start a sentence that way when it may work better connected to the previous sentence. There are many other conjunctions you can use instead, such as
yet,
however, and
although, to add more variation. The meaning and usage of these words is similar, though not exactly the same (so I recommend checking the definitions and some example sentences to make sure you understand how each word is used,) and can sometimes better express what you mean than if you say "but."
For example, I suggested connecting these two sentences in your essay and changing
but to
yet: "There should not be such a big divide between the rich and the poor
, yet all we care about are first-world problems." The sentences are still correct if you write them separately; however, seeing how they have a very direct relation to each other, they sound smoother if you connect them. The switch to "yet" is just an example of an alternative conjunction, not actually a correction -- "but" is perfectly fine here as well.