Since you have to argue both sides and this is for school, I'll try and give you a less common one for each side. Of course you'll have to expand on these hopefully they'll just start you thinking.
If one believes what is detailed in the book of Genesis, it could be argued that, we are inherently bad. As we have knowledge of what is sin, yet we continue to do it.
Since we were created in God's image we are essentially good. This is why 'bad' actions are noticed because they go against the trait of mankind that is being 'good'. Although individuals may be tempted to follow the 'bad' examples of others, we are only following an example and thus are not truly bad. We are inclined to follow and adapt our behavior to mirror the example of those who are deemed to be 'surviving', and that behavior may be 'bad' because it bends societal rules. Hence the individuals who are leading 'bad' lives or are thought to be 'bad' are merely a product of our environment. Suggesting humans are malleable, and in fact it is not us but the nature of our society which is inherently bad.
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Joey -Formerly *III.JVD.III*
I post from mobile the majority of the time, so if the above is incomprehensible, I apologize.