I do think that this book, to its credit, qualifies as both pleasant, unchallenging reading and as a work of national contemporary significance.
The novel's structure, using relatively short chapters, simple/simplistic characters, and direct moral statements/instruction the book is certainly attempting to be unchallenging as a text. This does not mean that it is unchallenging as a statement or as a work of art.
The moral, as overt and explicit as it is, represents a challenge - to see that justice is not always done, the good guy does not always win, and doing good deeds can put you in harms way. Populations can be corrupt and pretend innocence at the same time. In fact, this is often the case.
For its interests in these issues, the book remains relevant and significant.
I would be surprised to hear ANY teacher say his/her choice was that To Kill a Mockingbird is "pleasant, undemanding reading." Nope, any story written this well about the significance of racism in post-war society that becomes universal (because racism still exists today, unfortunately) should be described as a "novel of strong contemporary national significance," pleasant reading or not!
There are quite so many quotes from the novel in regards to this subject, it's hard to pick a few out. So, I thought I would mention a few that aren't usually at the forefront.
They're certainly entitled to think that, and they're entitled to full respect for their opinions... but before I can live with other folks I've got to live with myself. The one thing that doesn't abide by majority rule is a person's conscience.
Condemning Tom Robinson because of simple, outright racism was not in Atticus' nature. A man with an amazing conscience, he is able to impart this to his children. Evidence that he is able to impart this lies in the next quote:
It was times like these when I thought my father, who hated guns and had never been to any wars, was the bravest man who ever lived.
And a final example of contemporary significance that can apply to so many other negative aspects of our current society (including racism) is as follows:
Simply because we were licked a hundred years before we started is no reason for us not to try to win.
I would have to agree with the "novel of strong contemporary national significance." I am lead to this decision because of the many themes "To Kill a Mockingbird" holds.
First, the following quote refers to the fact that many people fail to truly identify courage.
I wanted you to see what real courage is, instead of getting the idea that courage is a man with a gun in his hand. It's when you know you're licked before you begin but you begin anyway and you see it through no matter what. You rarely win, but sometimes you do. Chapter 11
Many people may think that it is courageous to have a gun in ones hand. Here, Atticus is stating just the opposite.
Second, the following quote speaks to the fact that many people, and groups of people, fail to understand the importance of self-identity and acceptance.
They're certainly entitled to think that, and they're entitled to full respect for their opinions... but before I can live with other folks I've got to live with myself. The one thing that doesn't abide by majority rule is a person's conscience. Chapter 11
Perhaps on of the most relevant ideas expressed in the novel in regards to contemporary thought appears in Chapter 23:
The one place where a man ought to get a square deal is in a courtroom, be he any color of the rainbow, but people have a way of carrying their resentments right into a jury box.
As a society, many people still harbor prejudices which ran rampant since the beginning of slavery. This idea, over all others, still speaks to the racial prejudices which people hold to be truths today.