Your straw-man question has been duly noted.
Perhaps you could admit that you really don't know too much about God, and you would be interested in knowing why people go to hell. That would be a lot more honest than asking accusatory questions that have no answer.
It would be like if I were to ask you, "Why do you close the living room curtains before abusing your children?"
God doesn't "threaten" anybody. God lays down the law, He gives us the consequences for disobedience, then He allows us to make our own choices.
To assume that God threatens us, you should also accuse police for threatening to give you a ticket, or accuse judges for threatening to send you to prison if you break the law!
I have said it too many times to bother counting, but I will repeat myself yet again.
God sends people to hell for the same reason a judge sends criminals to prison - if they are guilty of breaking the Law!
Nobody will be in hell who doesn't deserve to be there, and nobody in hell will have to wonder WHY he or she is there.
If you have ever violated your conscience, which is a watered-down version of the Law (spiritually speaking), then you are guilty, period.
God owes you nothing! You have violated the Law, and you deserve the penalty, period.
HOWEVER - that's not the end of the story.
God is offering you an undeserved and unmerited pardon because Jesus Christ died to pay the penalty in your place - if you accept His offer and turn from your sins (i.e. repent).
God is not obligated to give you anything, but out of His great Love for you, in that while you were still a sinner in rebellion against God's Authority, Jesus already died on the cross in your place.
God isn't sending anybody to hell - He's trying to rescue them from hell, and you refuse His offer!
If you fell into a deep hole and you couldn't get out, and somebody threw a rope down to you, if you rejected his offer to rescue you and you died down in the hole, whose fault is it? According to YOUR theology, the guy with the rope is to blame!
If you had a cancer that was extremely and excruciatingly painful, inoperable, and somehow forced you to stay alive for the next 5 years, and then a doctor came along with a cure that he was giving away FREE, then if you rejected the doctor's offer and you suffered terribly for 5 years, whose fault would it be that you suffered for 5 years, then died? According to YOUR theology, it would be the doctor's fault!
If you sin, and deserve hell, and God is offering you an undeserved and unmerited pardon to get you out of hell if you would just TRUST Him, and you rejected His offer, then according to YOUR theology, it's GOD'S fault that you end up in hell!
Your theology is from the devil of hell, itself!
YOU are the one who is not legitimate. You go make riling accusations against God when He's offering you a way of escape!
"How can we escape judgement if we neglect so great a salvation?"