Answer:He let it go because he knew that he needed to blow off steam.
Step-by-step explanation:
"'I wish Bob Ewell wouldn't chew tobacco,' was all Atticus said about it" (217).
Jem and Scout describe their father as dry, but Atticus' comment about Bob Ewell is almost unresponsive. Nothing Bob Ewell says or does can rile Atticus up. In fact, nothing ever riles Atticus up to the point where he loses his self-control, self-respect, or dignity. On the other hand, some might say that Atticus was naive to think that Bob Ewell wouldn't do more than just threaten him. For example, Atticus is truly shocked when he discovers that Mr. Ewell actually tried to kill his kids with a knife in chapter 28. When Scout describes the attack to Heck Tate in chapter 29, Atticus interjects with the following:
"I can't conceive of a man who'd. . . I thought he got it all out of him the day he threatened me. Even if he hadn't, I thought he'd come after me" (269).
This passage shows that even though Atticus barely responded to Bob Ewell's threat at the time, he underestimated the depth of Ewell's intention, motivation, and ambition. At the time Bob Ewell threatened him, Atticus climbed into Bob Ewell's skin, but didn't understand as well as he thought he did. Little did Atticus know that had he really climbed into Ewell's skin, he would have seen rage and revenge.