He doesn't want people to know that he had kept a black woman as his mistress. Actually, he comes from a very good white family but he has to go so low to find desire and fulfillment from his black mistress. His white mistress even got pregnant and give birth to children, so it is right to say that she is her second wife. In fact, his white wife hadn't make a official divorce with him, so he was still legally married. So, Dolphus Raymond had actually committed bigamy, which is a serious offense and against the law of conduct. Like Mayell Ewell kissing Tom Robinson, which is a serious offense as a white woman had tempted a black negro, he had committed a much serious offense than this as he had even make a Negro pregnant, which is implorable.

So, as to hide this dark side of his, he had to cover up all loopholes and hide the truth to the Maycomb citizens as his reputation may crumble down to pieces if his terrible act had spread around. He had deceived his fellow citizens by tricking them to believe that the drink inside the bag was whiskey, making people believe that he is a lowly drunkard, but actually it was just plain old Coca- Cola. It turns out that Raymond has taken the psychological pulse of the town and had realized that:

"they could never, never understand that I live like I do because that's the way I want to live"

If the town believes that he does it because he is drunk, then they will shrug their shoulders and leave him alone, so they won't keep on questioning on his past life and he won't have a hard time explaining his own decisions. He would have a "peace of mind" and he can mind his own business, without bothering to defend and argued for his own actions. Better be known as a town drunkard than a negro-lover!