Why human trafficking should be stopped? I'm having a hard time wording things without sounding terrible, plus I can't think of the words I need.

I can definitely help you get started, but I can't write an essay for you. Additionally, your question points out an important part of writing. An individual writer has his/her unique writing style and voice. Your voice needs to come through in the essay.
The first thing that you need to decide on is a reason for why human trafficking should be stopped because that will allow you to complete a thesis statement. The thesis will basically state that human trafficking should be stopped followed by the reason that you have come up with. I have no way of knowing why you think that your wording is terrible, but I suspect it is because the reason against trafficking is too specific. Starting off an essay with too specific of an idea tends to choke the essay and not allow the writer room to explore different aspects of the topic. Try to pick a broader and more thematic reason why human trafficking should be stopped. I think one reason that could open a lot of writing avenues for the essay is that human trafficking is dehumanizing.
Saying that human trafficking is dehumanizing now allows you to explore the two main groups that the practice dehumanizes. It should be somewhat obvious that the people being trafficked and sold into various forms of slavery are dehumanized. They are treated like animals or a non-living product. I believe that it could be argued that human trafficking also dehumanizes the people in charge of the trafficking. In order to treat a person like a product, you have been dehumanized in a way that prevents you from sympathizing and empathizing with the people that are being trafficked.
https://www.endslaverynow.org/blog/articles/justifying-human-trafficking-the-mind-of-a-trafficker