Miss Maudie is trying to explain that Boo Radley's father's idea of religion is just as destructive of family life as alcoholism. She says that some kinds of Christians--she calls them "footwashers--" are overly concerned with sin. They equate any kind of pleasure with sin, and they also equate being a woman with being sinful. This kind of judgmental, hard, joy-killing faith destroys people's spirits, including the spirit of a child raised in that kind of environment.
Miss Maudie then states that a Bible in one person's hand is worse than a whiskey bottle in another person's hand--such as Atticus's. When Scout doesn't understand, Miss Maudie goes on to explain that even if Atticus were to get very drunk on a bottle of whiskey, he still wouldn't be as mean as some people are while sober. Some men, Miss Maudie says, are naturally hard and are made harder by religion. They are so worried about who is going to heaven and hell that they don't learn how to live in this world. When she refers to looking down the street and seeing the results, she is talking about the Radley family. As she puts it:
What I meant was, if Atticus Finch drank until he was drunk he wouldn’t be as hard as some men are at their best. There are just some kind of men who—who’re so busy worrying about the next world they’ve never learned to live in this one, and you can look down the street and see the results.