To what purpose, April, do you return again?

When April comes, I always think about the opening lines of T.S. Eliot’s The Waste Land. And today I read another poem that also mentions this month.

Spring
by Edna St. Vincent Millay

To what purpose, April, do you return again?
Beauty is not enough.
You can no longer quiet me with the redness
Of little leaves opening stickily.
I know what I know.
The sun is hot on my neck as I observe
The spikes of crocus.
The smell of the earth is good.
It is apparent that there is no death.
But what does that signify?
Not only under ground are the brains of men
Eaten by maggots.
Life in itself
Is nothing,
An empty cup, a flight of uncarpeted stairs.
It is not enough that yearly, down this hill,
April
Comes like an idiot, babbling and strewing flowers.

I wonder why this month has inspired such dark images, “life is nothing”, “an empty cup”. Poor April! Are you going to be the cruellest month?