In Christ's time the Jews believed in Purgatory and still do. Why don't Protestants? The Jews believe in Purgatory, why don't Protestants?
What Purgatory is; providing that the general impression among Protestants is correct; is a place where the dead await becoming sinless, and when that happens they are then admitted to Heaven. The fact that such a place existed until Jesus suffered on the Cross; appears to be proven by the following Scripture.

Matthew 27:52-53 And the graves were opened; and many bodies of the saints which slept arose, And came out of the graves after his resurrection, and went into the holy city, and appeared unto many.

Then when Jesus resurrected all those awaiting Heaven, were loosed from there, and proceeded to enter Heaven. Those beliefs are based on Several passages from the Bible. They are:

Job 14:12-15 So man lieth down, and riseth not: till the heavens [be] no more, they shall not awake, nor be raised out of their sleep. O that thou wouldest hide me in the grave, that thou wouldest keep me secret, until thy wrath be past, that thou wouldest appoint me a set time, and remember me! If a man die, shall he live [again]? all the days of my appointed time will I wait, till my change come. Thou shalt call, and I will answer thee: thou wilt have a desire to the work of thine hands.
Job 19:25-27 For I know [that] my redeemer liveth, and [that] he shall stand at the latter [day] upon the earth: And [though] after my skin [worms] destroy this [body], yet in my flesh shall I see God:  Whom I shall see for myself, and mine eyes shall behold, and not another; [though] my reins be consumed within me.
Daniel 12:2-3 And many of them that sleep in the dust of the earth shall awake, some to everlasting life, and some to shame [and] everlasting contempt. And they that be wise shall shine as the brightness of the firmament; and they that turn many to righteousness as the stars for ever and ever.
Hosea 13:14 I will ransom them from the power of the grave; I will redeem them from death: O death, I will be thy plagues; O grave, I will be thy destruction: repentance shall be hid from mine eyes.

All of there are prophesies from the Old testament, which precedes Salvation.
From the New Testament the following Scriptures appear to indicate that that place no longer exists:

Matthew 28:6-7 He is not here: for he is risen, as he said. Come, see the place where the Lord lay. And go quickly, and tell his disciples that he is risen from the dead; and, behold, he goeth before you into Galilee; there shall ye see him: lo, I have told you.

Jesus apparently negated the need for a place of atonement when he sacrificed his life on the cross.
Since the man Jesus took on all the sins of those who put their eternal faith in him, He also must be loosed from whatever interment he underwent for the three days he was in the Grave. That alone shows that all sins of those who are destined for Heaven are forgiven.
The following Scripture tells us that at his sacrifice people who are in their graves will come forth to judgment.

John 5:28-29 Marvel not at this: for the hour is coming, in the which all that are in the graves shall hear his voice, And shall come forth; they that have done good, unto the resurrection of life; and they that have done evil, unto the resurrection of damnation.

Matthew 27:52-53 would appear to indicate that the hearing of his call has already transpired. The part about resurrection of life, and resurrection to damnation, obviously will not happen until the great white throne judgment of the Revelation.
The following Scripture appears to tell us that at some time in the future Jesus will issue another call and that the elect will not be in any waiting place, but will be scattered throughout Heaven.

Matthew 24:31 And he shall send his angels with a great sound of a trumpet, and they shall gather together his elect from the four winds, from one end of heaven to the other.

The following promise of Jesus to the thief tells us that he will not go to a waiting place, but will go to Heaven to be with Jesus.

Luke 23:42 and 43  And he said unto Jesus, Lord, remember me when thou comest into thy kingdom. And Jesus said unto him, Verily I say unto thee, To day shalt thou be with me in paradise.