Question

Like a boil that can never be cured as long as it is covered up but must be opened with all its pus-flowing ugliness to the natural medicines of air and light, injustice must likewise be exposed, with all of the tension its exposing creates, to the light of human conscience and the air of national opinion before it can be cured.

What does this mean?

Answer 1

He's saying that racial injustice cannot be solved until it is brought out into the light, even if people don't like it.

He is using a simile to do this, "Like a boil that can never be cured as long as it is covered up but must be opened with all its pus-flowing ugliness to the natural medicines of air and light," Using 'like' to compare two realistically unlike things.

Answer 2

The sentence communicates a matter of fact tone so the answer would be " matter of fact"