That is only part of it and the scapegoat.
Norman! What did you put in my tea?

Your brain is toasted cheese. WWII happened because of a madman's lust for power.
There are 8.2 billion people in the world. 8.19 billion of them have never heard of and don't give a fuck about Charlie Kirk. Get over it.

Bill pitted the girls against each other, because he knew they loved each other.
Humans pit each other against each other all the time for power, control and dominance and considering the era it's set in, very appropriate. WWII happened soon after, devised by the elitists to lift the world out of 30's depression.
Norman! What did you put in my tea?

Without asking Stephen King, I personally believe this is directed at "He['God'] killed them with their love, its like that all over the world"
Love is a huge umbrella, it can create, but it can destroy.

In another way it could also mean John himself. As it's his love for life and trying to save the girls that got him put on death row. He didn't mean that at that point but I think it's like a hidden meaning in the film

Aside from the obvious that Wild Bill threatened the girls with death if either screamed and alerted others of their kidnapping I was wondering how Coffey's comment might come into play at his execution since Paul and his other work colleagues like Brutal and Dean grew to love Coffey and knew of his innocence. Yet, Paul hesitated to call the order and shakes Coffey's hand for the last time and hears what's on Coffey's mind for the last time i.e. "He kill 'em with they love. That's how it is ever' day. All over the worl'" I thought to myself that Coffey in that moment put Paul in an unenviable position and so it was like Coffey had threatened Paul saying i.e. If you love me kill me. And so Paul's love for Coffey was so great that he felt he couldn't choose any other way and chose to give the order to end his life. I don't know if I could do that though personally myself unless the person was in unimaginable physical or emotional pain. Even then I think I'd hesitate to the point of paralysis.

A wife knows that her husband cheats on her, she loves him, he pumps HIV into her, love hurts.
Spoiler alert for them spoil sports out there! Y'all like spoiled milk, stop crying over it!

He used their love for each other against them. Remember that Wild Bill asked each little girl "do you love your sister? If you make any noise I'll kill her". That's what he meant.

There's an episode of Forensic Files called "Daddy Knows Best" and it's about a man who murdered his wife because she found out he was molesting their son and daughter. In the interview with the daughter, she said that the told the stepmother about what her father was doing and when he found out she said something, he gave her the same threat. If she told her stepmother or anyone else about what he was doing to them he would kill her brother and her brother said anything, he would kill her. Every time I hear that, the line "He killed them with they love, they love for each other" comes to mind. The man's father was the one who helped the police catch him by tracing a phone call he made to him.
Stop using sex as a weapon.

Yeah thats what i thought..just had to know!

"he killed them with they love" basically meant, he managed to kidnap them in the first place by threatening the sister. He told one that if she screamed, he would kill her sister, then vice versa. The fact that they each loved each other, meant neither screamed. Hence, he was able to kidnap them then subsequently rape and murder.
No power in the verse can stop me