In Catholic belief, purgatory is not condemnation: It is a place of penance and purification (note the Latin root in common with "purging", "purgare", meaning to purify), in preparation for one's admittance into heaven, cleansing the sins of the deceased.
Ultimately, a soul will either be admitted into Heaven, or condemned to Hell. Purgatory is neither, but rather a temporary state/location, where those who die in God's grace ("in Jesus Christ"), but who still bear the stain of their sins are cleansed prior to admittance in to Heaven.
This is described in (the admittedly difficult to parse at first glance) 1 Corinthians 3:11-15:
"For other foundation no man can lay, but that which is laid; which is Christ Jesus. Now if any man build upon this foundation, gold, silver, precious stones, wood, hay stubble: Every man's work shall be manifest; for the day of the Lord shall declare it, because it shall be revealed in fire; and the fire shall try every man's work, of what sort it is. If any man's work abide, which he hath built thereupon, he shall receive a reward. If any man's work burn, he shall suffer loss: but he himself shall be saved, yet so as by fire."
C.S. Lewis, who believed in purgatory (despite being a Protestant Theologian, although best known now for his children's literature series the Chronicles of Narnia), described it in analogy in a letter, saying:
"Our souls demand Purgatory, don't they? Would it not break the heart if God said to us, 'It is true, my son, that your breath smells and your rags drip with mud and slime, but we are charitable here and no one will upbraid you with these things, nor draw away from you. Enter into the joy'? Should we not reply, 'With submission, sir, and if there is no objection, I'd rather be cleaned first.' 'It may hurt, you know' - 'Even so, sir.'
I assume that the process of purification will normally involve suffering. Partly from tradition; partly because most real good that has been done me in this life has involved it. But I don't think the suffering is the purpose of the purgation. I can well believe that people neither much worse nor much better than I will suffer less than I or more. . . . The treatment given will be the one required, whether it hurts little or much.
My favourite image on this matter comes from the dentist's chair. I hope that when the tooth of life is drawn and I am 'coming round',' a voice will say, 'Rinse your mouth out with this.' This will be Purgatory. The rinsing may take longer than I can now imagine. The taste of this may be more fiery and astringent than my present sensibility could endure. But . . . it will [not] be disgusting and unhallowed."
- C.S. Lewis, Letters To Malcolm: Chiefly on Prayer