The corrupt, the purity, and the way we are

How can a man who promised himself to work for the people end being so corrupt? I have been thinking about this problem (in the sense of transformation) for several days now. The fact is that no men become corrupt suddenly. In other words, let us say this change is done, first, with small steps, baby steps.

Moreover, this is the dilemma that haunts men in every aspect of life, good or bad. In ancient Greek men wonder and continuously ask themselves about the purpose of life. Many felt into the idea that the 'Logos' of life was to pleasure oneself incessantly, asking for more every time; and with each new episode of pleasure, their need to seek more innovative ways to satiate a hunger that became increasingly dangerous and pernicious.

Only one taste, one single touch could get you into an overfall of desire. This can be translated to the corruption of the politician, the intellectual, the philosopher. Corruption means that something has been altered, atrophied, debased. And the corruption of the pure and beautiful are the kind of denigration that deals more damage to the collective mind of society.

Are purity, and the desire to be pure, wrong? Why people nowadays see it as wrong? Why we ask so much less from ourselves when it comes to being a better (pristine) person?

I don't want to belong to a society that drills into the mind of young people ideas of moral and ethical imperfection. The nature of men, by default, is always asking for more, whatever the men choose to go for: good, bad, or lame. If a man decides to be bad  eventually this will grow, and it could only be stopped for two reasons:

1) The corrupt imminently knows he is going to be caught and for that reason stops, for a while.
2) The corrupt dies.

Not only that, the corrupt will make his case to justify his deeds. At this moment you know he has normalized his behavior because the evil has taken his eyes, ears, and tong. This person is completely transformed and cannot be trusted again, because for that purpose he would have to be renewed.

I just keep seeing this pattern happening continuously, incessantly, and it is taking a toll on me.