I know in a society that is entirely secular, it's hard to believe anything exists beyond the physical realm. I've witnessed the manifestation of good and evil before I turned 18. You can call me whatever names that came to mind, I've probably heard them a hundred times over. All I can say is that if you are faithless, want nothing to do with religion, you won't have to worry about opposition in terms of the forces of darkness (spiritual). They know you are unlikely to find the truth due to your stubbornness to your beliefs or non-beliefs if you wish. There's no point of oppression to a person who willingly accepts their agenda.
Hence in secular countries where people openly renounce God and anything supernatural, you are less likely to find people who testify to these things. Even most Christians you meet will not have experienced the supernatural, they are more carnal (physically) minded. People in secular societies already do the work (knowingly or unknowingly) for these forces of darkness which past generations of my family have come to face.
That being said, those of you that follow global news and events will be aware of the push to form a one world government, religion, and currency. We became more accustomed to this after the event of 9/11, before that it was the "conspiracy theorists" and "bible thumpers" who were crazy for suggesting this agenda. This agenda that is being presented is now the physical manifestation of the plans for the forces of darkness. Their spiritual agenda is subservient devotion to only one being who I'm sure most of you will be familiar with as Lucifer or Satan.
Yes, you may suggest God is no different, however God is worshipped 24/7 by willing beings both in heaven and on earth, both human and spiritual beings. God won't force you to worship and obey Him and nor will I. Lucifer on the other hand, in his quest to be God will go at lengths to deceive many to worship him. The implementation of the one world order will be his last play. The world may seem calm to many especially in secular societies, but there is a war raging on in the heavens which will and is slowly making it's way into the physical world.
I've also see the Pope pop up in the discussion here. He is one of many pushing the forces of darkness agenda, calling for all religions to come as one for "peace and security". The practices that goes on behind closed doors at the Vatican is the main reason for the breakaway of Protestants and Evangelicals. Unfortunately, the forces of darkness have slowly infiltrated those as well to taint the truth and hide it from people. Prove of this is the way "Christians" behave today. I'm sure some of you atheists have lots of experiences in calling out the hypocritical behaviour by some of them.
In summary, the only chance you have of experiencing the world beyond the physical realm is one through the forces of good those obedient to a Creator like no other. However this chance diminishes really quickly once you dismiss the existence of God. Remember, you currently have no opposition in the forces of darkness because of your current stance and non-belief.