Here is a brief Wesleyan account of the root causes of social evils. In a word, the cause is sin.
In his treatise on Original Sin, John Wesley gives the following example of the ways misery and poverty are ultimately traced back to sin.
Many families are miserable through want. They have not the conveniences, if the necessaries, of life. Why have they not? Because they will not work: Were they diligent, they would want nothing. Or, if not idle, they are wasteful; they squander away, in a short time, what might have served for many years. Others, indeed, are diligent and frugal too; but a treacherous friend, or a malicious enemy, has ruined them.; or they groan under the hand of an oppressor; or the extortioner has entered into their labours. You see, then, in all these cases, want (though in various ways) is the effect of sin. But is there no rich man near? none that could relieve these innocent sufferers, without impairing his own fortune? Yes; but he thinks of nothing less. They may rot and perish for him. See, more sin is implied in their suffering.
Wesley argues that miseries of many kinds — from that of individuals to that of nations — can be traced back to sin. And these sins are always a case of willful actions or omissions. Wesley did not look to impersonal or systematic causes of social evils. Sin was the cause and sinners were in one way or another the agents of misery.
The role of the church in the face of these things was to identify the sin, convict the sinner, and thereby relieve the suffering and redeem souls at the same time.
This is slow work, of course. And in a culture where people reject the gospel out of hand, it is a solution that many people cannot even contemplate. In such cases, it falls to the church to care for those who suffer, to continue to witness to the gospel, and to lay down its life for others so long as sin runs free.
This is what the church has done through the ages when it is at its best.