As Muslims we believe in two basic forces that can draw us into bad behaviour and wrong-doing. One is external, and one is internal. There is Shaytan, and there is the nafs. We do not believe that people are innately good or bad, but that they have the innate potential to be either, and indeed, to be both simultaneously.
It is fairly important to clarify that when Allah says that “all human beings sin” He did not say “all human beings are sinful”; that is a significant difference. A person’s life is comprised of both good deeds and bad deeds, and these will all be weighed against each other on Judgment Day.
The nafs, or the Self, is more or less similar to what Carl Jung described as the Shadow; it is the dark side of our nature that we are continuously grappling with, and to which we often succumb, though to varying degrees. Muslims are aware of this perpetual struggle, and the added factor of the external temptations and promptings and incitements of Shaytan which further complicate our efforts to live a moral and disciplined life.
Despite what most people think about Islam; that it is harsh and unforgiving, our awareness tends to make us more compassionate and less judgemental when someone stumbles; even if that compassion does not negate the necessity of punishment.
And we are emphatically encouraged to conceal the misbehavior of others, to address wrong-doing one-on-one rather than in a public forum, and to refrain from prying into the private affairs of other people looking for their sins. We all know that every one of us is struggling, and that every one of us fails in that struggle from time to time; and we know that righteousness does not mean never failing, but always continuing to struggle.
It seems to me that the standard shock and vilification non-Muslims display about the misbehaviour of others is quite dishonest, or at best very naive and self-deceiving. It seems to be a denial of the fact that everyone has a dark side and that everyone is capable of succumbing to urges and confusions which cause them to behave in ways radically contradictory with their own moral aspirations.
No one is their “best self” all the time, and everyone’s “worst self” can be utterly horrendous, disgusting, and dangerous. This is something that we all must acknowledge, about ourselves and about each other.
We have all been subjected, at one time or another, to other people’s ugly descent into their worst selves, and it is always hard to know what to do and how to react. But, by the same token, others have been subjected to our own ugliness at one time or another and I would argue that across the board, the people who have reacted to us with understanding and pity tend to become dearer to us and help us to become better. And this, after all, is what we should be trying to do with each other.