Because I was a good atheist. I managed to think my way right out of secular humanism and into something far better because my curiosity and desire to do so was sincere. I was one of those cold/hot people that Christ will not spew from his mouth. It's the lukewarm he knows will never change, they are already consigned to hell. There is still hope for a passionate fool if he will only truly search his heart for what it has known since before he was even born.
I'm a Calvinist. I don't drag God down to the level of a human being. I know he is omnipotent and outside of time. I know my brain cannot even be compared as a fraction to his, because his is infinitely wise and merciful and his intelligence cannot even be called intelligence, because it is unbounded and without limitations.
Calvinists don't believe anybody has free will or really does anything on their own. God knows before he created the universe who his children are. According to scripture, God knows everything. Some vessels he makes for the fire. Some he doesn't. If you feel true remorse at your violations of God's commandments, you are one of his children. If you don't, you aren't and never can be. Christ is there for people to find out what the Lord God already knows. Repentance is a gift of God. It doesn't come from you. Could you even change a single hair of your head white or black? Not so much as a hair.
Everybody knows who is who and what is what. Satan knows who his children are, he can see more clearly than any human being. All that remains is for human beings themselves to discover who they are and to awaken to their father - be it God in heaven or Lucifer, the angel of light. Their actions tell you who they are - it's the fruit of their tree that tells you what they really are. There is a popular pagan idea that God is competing with Satan for souls - when in fact, God isn't competing with anybody for anything. Satan kneels at the foot of God as his servant when he is told to do so and is not permitted any power beyond what he is given. It's like Willy Wonka's front man in CHARLIE AND THE CHOCOLATE FACTORY. God's servant is given a commission to offer everlasting gobstoppers, even as God himself knows in advance who the good and bad children are and what their response will be. Like Gene Wilder's character in that movie, the wicked man believes Willy Wonka himself is wicked, when in fact Wonka never does anything to anybody for any reason - they do it to themselves. The bad kids get to try out whatever appeals to them and they can be counted on to ignore Mr. Wonka's pleas and instructions to them. Willy Wonka knows the bad kids are going to drink from the chocolate river and try out the forbidden blueberry gum - they're bad children. He knows that perhaps Charlie is going to disobey him and try out the fizzy drinks ... but he also knows he will forgive Charlie and welcome him into his arms at the end, because deep down Charlie is a good child, not a bastard like the others.
There are a lot of people in our civilization who don't behave all that differently from the people infected with the rage virus in 28 DAYS LATER. They lie, kill, curse, sneer, swear, destroy, steal, rape, stab, shoot and tear at anything that comes in range. They will tell you on television that it's all your fault - you made them this way. Deep down, they must not have a conscience even to say such a thing. There is no conviction of sin, no remorse, no repentance in them - just grievances and boundless evil. These people tell you what they are by their fruits. Their tree is composted in sin and has roots that go down to hell. There aren't enough Oompa Loompas in the universe sufficient to squeeze the rotten juice out of these bad kids. They were hell's property from the day they were born.
In the modern era, everything bitter is called sweet. Sweet is called bitter. The wicked say they are the standard of good and that the righteous are the sinners. There isn't a single thing in the world that isn't stood on it's head and completely inverted against all healthy value systems. Suicide is good, death is better, we are told. Childlessness is a virtue and self-loathing is a blessing. Whatsoever destroys us, we are encouraged to embrace secure in the knowledge our acts will be lauded as proof of our ethical vindication.
My conclusion - and I do have one - is that you should judge people by their fruits. Not what they say or what they claim to believe but rather according to their actions. Especially concerning Christianity, you must never condemn Christ for the multitude of the damned who profess to love him. Their actions tell a different story. They're Krisschans, not Christians.
I began to change by judging secular humanists by the fruit they bore and before I knew it I was a Christian. In order to be a good secular humanist and answer to the highest of all human values, it is necessary to become a Christian. There is no other way of fulfilling the goals that secular humanists claim to aspire to.