Why does the jury find Tom guilty? in to kill a mockingbird

They are racist to the handicap.

Explanation:Tom is found guilty of raping Mayella although reasonable doubt and Tom's handicap is proven.

because the jury was racist

Explanation:

The jury’s decision to convict Tom Robinson for a crime he clearly did not commit plagues Jem as an intolerable miscarriage of justice. The most obvious reason justice isn’t served is because the jury’s overwhelming racism prevents Tom from getting a fair trial. Another reason the jury finds Tom guilty is that Mayella Ewell and her father Bob, both perjured themselves on the stand. In addition to the presumption of an impartial jury, the justice system operates on the assumption that witnesses will tell after being sworn to testify. But both Mayella and Bob lied rather than admit that Mayella tried to kiss Tom. Tom’s race, combined with the Ewells’ lies, proved enough for the racist jury to find Tom guilty, even in the face of overwhelming evidence of Tom’s innocence.