“This case is as simple as black and white.” Atticus is speaking with irony here. What do his words really mean?

Atticus simply means that the case is pretty straightforward.

The members of the jury do indeed see the case as black and white, but not in the sense that Atticus means it. Their understanding is much more literal

It is easy to tell the difference between the colors black and white, just like it is easy to tell that Tom Robinson is not guilty is what atticus means

yeah! it's really me with my homework, you should try it!

needs an explanation