Wars are fought because of failed or unattempted diplomacy. Someone wants what you have (diplomacy). Anything. You won't give it to them (failed diplomacy). They try to take it away from you (war). For any reason.
Seculars are the war mongers. In modern times they get fat and wealthy from war. They can profess any religion but in fact they have none. War can be in the name of anything that is convenient to justify it but it all comes down to the fact someone has something someone else wants and that someone else is going to have it. You can blame it on anything you heart desires to but it still comes down to greed and dishonesty. And ignorance of the facts.
Chess was invented by a general officer to teach tactics to his subordiant officers. Now that was some free thinking. He was not a Christian. I beleive he was Chinese and followed Buddha. Or an Indian Hindu.
The most successful warriors have to be free thinkers. Many in the US military are Christians. They aren't fighting because God told them to. Or to further their religion. Intimately, at this time, they are fighting for oil and control of a region. They are fighting well but the goal is not as easy as the aggressor leaders (us) thought it would be. Most people who think they are "free thinkers" allow themselves to be conned into extreme actions because it is the "correct" way to conduct themselves. The Secular religion is based on a "correct way to be" set-up by the very people who are running the con. And you think your right! You've fooled yourselves into into thinking the con being run on you is right!
Here's an example of your "right"! The hole in the Ozone above the Antarctic Circle. Cost a lot of money and time to fix. Wrong! The gasses used by the scientists proved to be "hot house gasses". And the hole is as big as it ever was. It's a natural phenomena discovered during WW2. That's pretty far back. And we didn't start to "FIX" it until the 1970s. Now that's some "free thinking". You gotta look at what these people say and do and check it out before you jump into the muck. Look at what they say will happen and when it doesn't you can feel good about yourself because you didn't fall for the lies they espouse. Most of their stuff is designed to separate you from what you have.
It doesn't matter how altruistic your intentions. When you force them on others who don't want them, it's evil. If you cause harm to others by forcing your, altruistic, intentions on others who don't want them, it's the ultimate evil. It works both ways in war. Both sides come to the conclusion that God is on their side and they're going to "win" against the "evil empire". Or God will save them from harm. Unless your secular and don't believe in God. Then you take what you get. It's your fault. You shouldn't have been there in the first place. What ever was going on in your Mind?
All Christianity is is a system of social interaction and there are rewards offered by the system. They may, or may not, be real rewards but doesn't it make sense to hedge your bets a bit just in case it is? It's a pretty good system too and it's the only one where the chief prophet says he's the Son of God. The rest do not. Islam even says Jesus is the Son of God and will return to this veil. Whoa! Now that's some free thinking!
All wars are caused by "free thinkers". They think that what they want to "liberate" from anyone is free. At least that was what they were told