Our Lord wishes to teach us that there is hope for us as long as we live.
He does not cut us off forever, unless we DIE in our sins. If we sink into the evils of prostitution for 10 years, but then REPENT of that sin, stop doing it, and return to Our Lord with love in our heart for him (and go to Confession to a priest of His Church, which is an institution He founded), He will be extremely happy with us. Especially if we also have a firm resolution to never sin again, and intend to do penance to do our best to atone for our sins. Our Lord must love someone who follows his commands so perfectly! ("Do penance", etc.)
He won't label us, or even hold against us, a sin that is repented and atoned for. We are not "Prostitutes", "Thieves", "Blasphemers", "Gossips", "Gluttons", "Drunks", "Fighters", etc. in God's eyes unless we are STILL guilty of those sins.
Incidentally, God loves us in proportion to how much we love Him. Mary Magdalen DID love Our Lord very much -- she spent the rest of her life in penance, and tradition says she never committed another mortal sin after her conversion.
The lesson Our Lord was teaching us by the parable you speak of is this: The religious life is a higher calling than the life of a layman. Martha was the "active" life, Mary was the "contemplative". The contemplative life IS higher, though not everyone is called to it.
Someone has to grow the food, have children, etc. but that doesn't mean the contemplative life is not the greatest calling a human being can aspire to.
Humans are less inclined to "wipe the slate clean" and give people a second chance. God is so much greater than us. When a prostitute truly converts and becomes a saint, God completely overlooks the sin that has been forgiven. Man could never be that great.
God loves a fervent, repentant woman (that used to be a prostitute) much more than a physical virgin who is lukewarm in her love of God.
Where there is breath, there is hope. This life is a "time of mercy". Even the worst sinner here can take comfort in the fact that he can still repent and atone for his sins. But after death, sinners must abandon ALL hope...
Matthew