The key word to focus on in this question is “allow.” God does allow people to go to hell but He does not force anyone to go to hell. People are, by their own nature that is expressed in their own free will (that God allows), on their way to hell already (Eph 2:3) Among them we too all formerly lived in the lusts of our flesh, indulging the desires of the flesh and of the mind, and were by nature children of wrath, even as the rest. The good news of the gospel is that God actually provides a way for people (“But God…”), using their own free will, to stay out of hell (Eph 2:4) But God, being rich in mercy, because of His great love with which He loved us, even when we were dead in our transgressions, made us alive together with Christ (by grace you have been saved). It is actually “people” and not God who  judge themselves into hell using their own free will (John 3:17-18). For God did not send the Son into the world to judge the world, but that the world might be saved through Him. He who believes in Him is not judged; he who does not believe has been judged already, because he has not believed in the name of the only begotten Son of God.

God, by His own nature (loving, holy, sovereign), comes to man to draw him to salvation from hell, not to force him to go to hell. God does not force people to go to the place that He has made provision for to stay out of. God is sovereign but that sovereignty does not cancel out the free will that He intentionally provided for man. It's also important to remember that God does not desire that people go to hell. He desires that all men come to salvation (1 Tim 2:4). He wants none to perish (2 Pet 3:9)

The key theological concept to focus on with this question is the holiness of God. Judgment must be an option; God is holy with respect to man. If man’s free will decisions do not have any repercussions, then God is not being holy/integral with respect to man and his free will. If judgment is not an option, then a lack of judgment is not an option either. This would leave man hopeless. Holiness requires the possibility of both a “right” and a “wrong” lest there is no actual free will decision in the first place and God’s sovereignty and holiness is a farce. God’s provision of salvation must not ignore judgment; God is holy with respect to Himself. God’s solution for the problem of sin must include judgment. He cannot just “wink at it” or act like it is not there or He would be a liar. It must include a propitiation for sin; that is, a satisfaction for the requirement of judgment that He pays for Himself (1 Jn 2:2). People do not have to go to hell, not because they are not judged, but because that judgment has been paid for. God allows people to go to hell because people allow themselves to go to hell when they “insist on” holding on to their own judgment instead of accepting that God took their judgment/paid for their sin (Eph 1:7).

Like the rest, we were by nature deserving of wrath. Ephesians 2:3

For God did not send his Son into the world to condemn the world, but to save the world through him. John 3:17-18

This is good, and pleases God our Savior, who wants all people to be saved and to come to a knowledge of the truth. 1 Timothy  2:4

Instead he is patient with you, not wanting anyone to perish, but everyone to come to repentance. 2 Peter 3:9

He is the atoning sacrifice for our sins, and not only for ours but also for the sins of the whole world. 1 John 2:2

In him we have redemption through his blood, the forgiveness of sins, in accordance with the riches of God’s grace. Ephesians 1:7

A systematic study of the doctrine of salvation (soteriology) and the doctrine of the Church (ecclesiology). Special attention will be given to the plan of redemption and the contents of the gospel message as it is seen in the incarnation, life, death, resurrection and ascension of Jesus Christ. Special emphasis will be on the nature and working of the kingdom of God. The Gospels and Jesus’ teachings will serve as the specific source of the study.

Is Hell for Real or Does Everyone Go To Heaven?
Timothy  Keller