Atticus is doing the right thing by defending Tom Robinson?

His evidence was that Tom's left arm was completely useless because it was mangled in an accident when he was young. It got caught in a cotton gin (a machine used to separate cotton seeds from the cotton) and he's never been able to move his LEFT arm since. He also points out that Meyella's bruises and injuries were primarily on the RIGHT side of her face. Now if you piece the puzzle together, then you realize, that if you're using only your RIGHT arm to punch someone, attempting to hit someone on the RIGHT side of THEIR face wouldn't have done any damage. [Try it with a friend if you don't believe me]

Furthermore, Atticus asks Bob to sign his name on a piece of paper, and finds out that Bob IS LEFT HANDED which you as a reader should obviously know what actually happened by now.

Also, it's kinda hard to believe that a girl could be raped by a man with only one arm if she tried to fight back... Like seriously who would believe a guy who had one arm could pin a flailing girl down and still be able to rape her? REALLY?!