“is a God who only saves some of His children a moral monster”
He saves ALL of His children. The rest have rejected Him and are not His children.
Mathew 7: 13 “Enter through the narrow gate. For wide is the gate and broad is the road that leads to destruction, and many enter through it. 14 But small is the gate and narrow the road that leads to life, and only a few find it.
Only a FEW are saved. MANY are not.
John 10:25 Jesus answered, “I did tell you, but you do not believe. The works I do in my Father’s name testify about me, 26 but you do not believe because you are not my sheep. 27 My sheep listen to my voice; I know them, and they follow me. 28 I give them eternal life, and they shall never perish; no one will snatch them out of my hand. 29 My Father, who has given them to me, is greater than all[c]; no one can snatch them out of my Father’s hand. 30 I and the Father are one.”
Luke 20: 35 But those who are considered worthy of taking part in the age to come and in the resurrection from the dead will neither marry nor be given in marriage, 36 and they can no longer die; for they are like the angels. They are God’s children, since they are children of the resurrection.
John 1: 11 He came to that which was his own, but his own did not receive him. 12 Yet to all who did receive him, to those who believed in his name, he gave the right to become children of God — 13 children born not of natural descent, nor of human decision or a husband’s will, but born of God.
Romans 8:14
For those who are led by the Spirit of God are the children of God.
Galatians 3:25 Now that this faith has come, we are no longer under a guardian. 26 So in Christ Jesus you are all children of God through faith, 27 for all of you who were baptized into Christ have clothed yourselves with Christ.
1 John 3:1
See what great love the Father has lavished on us, that we should be called children of God! And that is what we are! The reason the world does not know us is that it did not know him.
Revelation 21:6 He said to me: “It is done. I am the Alpha and the Omega, the Beginning and the End. To the thirsty I will give water without cost from the spring of the water of life. 7 Those who are victorious will inherit all this, and I will be their God and they will be my children. 8 But the cowardly, the unbelieving, the vile, the murderers, the sexually immoral, those who practice magic arts, the idolaters and all liars —they will be consigned to the fiery lake of burning sulfur. This is the second death.”
ALL are NOT God’s children.
“All that the Father giveth me shall come to me; and him that cometh to me I will in no wise cast out.” (John 6:37)
He will indeed save every single one of His children. Those given Him by the Father will be saved. They hear His voice and follow Him. “My sheep hear my voice, and I know them, and they follow me.” (John 10:27)
But consider the stunning implications of the passage immediately preceding verse 27: “Then came the Jews round about him, and said unto him, How long dost thou make us to doubt? If thou be the Christ, tell us plainly. Jesus answered them, I told you, and ye believed not: the works that I do in my Father’s name, they bear witness of me. BUT YE, BELIEVE NOT BECAUSE YE ARE NOT OF MY SHEEP, as I said unto you. (John 10:24-26)