In Dante's Inferno, people who were neutral in life are treated just as harshly as those who sinned.
These are the "uncommitted" who chose no side. They are rejected by both Heaven *and* Hell.
Lukewarm souls are made to wait forever in the "Vestibule of Hell". They're stung by wasps while they run around in pursuit of a meaningless white banner (in punishment for standing beneath no banner in life).
Even worse, their blood and tears flow from their faces onto the ground to be consumed by maggots. Why?
In Christianity, Christ's blood is shed for man's salvation, and the blood of the martyrs is considered the seed of the Church. To bleed — whether literally or metaphorically — for a worthy cause is a great act of love.
But in the case of the lukewarm, their blood merely feeds maggots. "You shall know them by their fruits," Christ says, but the only "fruit" the lukewarm produce is nourishment for worms.
Dante himself was exiled from his hometown of Florence by a rival faction after years of civil conflict. His dislike of the lukewarm stemmed from those who sat on the sidelines and did nothing while his sentence was handed down — those who let injustice slide and were more concerned with protecting their own lot in life.
Dante doesn't even give them the courtesy of mentioning them by name in his Inferno. The "uncommitted" are all nameless.
His warning to the spineless is thus:
Stand for nothing, and nothing is what you'll become.