In Romans 1:21-25, we see people who knew God, but failed to give Him glory or thanks. Thus God gave them up to futility and darkness in their thinking. Then God gave them up to uncleanness in their hearts.
What biased them to reject God? The answer is often bitterness toward bad or absent fathering in childhood. (http://www.leaderu.com/truth/1truth12.html)
They pretend that either God doesn't exist or God couldn't be knowable. These positions are called "atheism" and "agnosticism", respectively.
Without God, there is no moral standards or accountability. (Existentialism) Do whatever you want; just don't get caught. Or be powerful enough to intimidate people to silence.
Without God, there is no foundation of truth or reason. (Relativism) Logic is meaningless without a basic foundation of truth. Words don't logically mean anything; they just have emotional value that can be used to get your way.
Without God, nothing has any significance or value. Our instincts may sway us to do things, but to what end? Others may sway us to say and do things, but what gives them any wisdom or authority? Everything becomes a real life exercise in trivial pursuit. People have no point, no purpose, no inherent value. Despair and suicide are commonly the result of this position.
Psalm 1:1 shows this progression: "Blessed is the man who walks not in the council of the ungodly, nor stands in the way of the sinners, nor sits in the seat of the scoffers...." For further information on this position, read the book of Ecclesiastes in the Bible.
In order to avoid the crushing negativity and despair of the above, people go off into a form of insanity. They pretend there is significance in humanity, nature, self, etc., despite the logic of their godless position. For more information on this position, read Romans 1:21-23.
Considering humanity to be one's highest object of devotion is called Humanism. The United States Supreme Court has declared Humanism to be a religion, since it has an object of devotion and a moral code derived from that object. (Torcaso vs. Watkins)
Humanism comes in many flavors: Marxism, Capitalism, Socialism, Fascism, etc. The common thread is "the Good of Humanity"; they just have drastically different ways of trying to get there. This has caused terrible wars among Humanists in the past.
"The Good of Humanity" says nothing about the individual. People have no value outside of God's love for them, so individuals are often used, abused and killed by Humanists.
Humanity doesn't care about Humanists. People just want to be left to do whatever they want. Herding people around 'for their good' is never appreciated. The harder the Humanists try, the more they simply repress humanity.
Humanists don't "live on in history". The history books are constantly being modified these days to fit the latest fad in political correctness. George Washington would scarcely recognize himself in the latest school history books.
This is idolatry and is under the curse of God. Read Jeremiah 17:5-10 for more information.
Considering nature or 'mother Earth' to be one's highest object of devotion is called Naturalism. Civilization and human population growth are seen as enemies of nature, to be fought. Unfortunately, if meteor strikes don't take out nature, the sun will eventually grow and consume the planet. The universe itself is gradually sinking into darkness that won't support life, due to entropy.
Witchcraft and Shamanism worship nature and draw power from demons who live in nature. They and their children have a higher incidence of insanity and disease, due to God's curse on this activity.
For more information, read Galatians 4:1-9.
Considering personal pleasure, power and status as one's highest object of devotion is called Hedonism or Selfism. Doing "whatever turns you on" means people around a Selfist are going to be rudely treated or neglected. Since they live for the 'now', they are also the enemy of their future selves, as well. They make pathetic old people - if they survive that long.
The New Age is an attempt to appropriate knowledge and power through dark sources that happen to be demonic. It confers godhood and multiple reincarnations to its adherents. Unfortunately, the godhood status doesn't work when problems occur. The reincarnation is only for the demons that infest them. Their 'prior lives' can be cast out in the name of Jesus Christ.
Satanism is the worship of Satan. It is the ultimate grab for illicit pleasure, power and status. They can get it, but their end is extremely bad. Satan hates them and is only tolerating them until their usefulness is gone.
The occult powers can be defeated by the power of the God of the Universe. Christians can use the authority they have been given to do the job.
When faced with the folly of their ways, these atheists/nihilists/escapists can't defend their position. They must suppress truth and honest inquiry with other means. (John 3:19-21)
Personal attacks, ridicule, out shouting, threats and sabotage are the simplest and most direct. Slander and libel are used to discredit the source and mute the effectiveness of the message. All of these things happened to Jesus and His disciples. (1 Peter 4:2-6)
A more subtle attack is to pretend to represent the source of truth and promote the lie. Some false Christians can be found in most churches. (2 Peter 2:1-22)
Another attack is to try to infiltrate & subvert the source of truth to get it to promote the lie. There are organizations that look like churches, but don't represent Jesus Christ of Nazareth or His gospel. Unitarianism, Watchtower Society and Mormonism are a few examples.
A false religion complete with an internally consistent world view can protect the followers from the truth. It also can be used to coordinate an attack on the truth. Examples abound all around us: Islam, Hinduism and Scientology are but a few examples.
Humanists are trying to subvert all religions, true or false, to fit under the umbrella religion of Humanism. These counterfeit religions are shorn of any differences that conflict with Humanism or any other religion. Any exclusive claims like John 14:6 are anathema. Since Humanism has no supernatural elements, anything supernatural is excluded from these counterfeit religions. Please note; they don't try to subvert occult religions like witchcraft and Satanism... Ultimately, these religions will infiltrate & subvert Humanism.
Lastly, the honest people can be jailed, sent to Gulags or killed. All for the sake of an indefensible lie.
Telling these people of the folly of their ways will only get you hurt. Unfortunately, we are to "answer a fool lest they be wise in their own eyes." Look up "folly" and "fool" in the book of Proverbs.
God still loves them. God is still allowing them their free will, in hopes that they will repent. Our job is to pray for their salvation. Pray that God's love would reach their hardened hearts. Pray for their future faith, hope and love.
Bind any spirits of blindness, deafness, confusion and scrambling on their lives so the demons can't stop them from receiving truth. When God gives you the open door, speak to them about the truth and love of God through Jesus Christ of Nazareth. When they meet Jesus, this whole fabric of lies will fade away.