Cain committed murder even while knowing that it was a sin and tried to cover it up. This boy committed murder fully believing that it wasn’t wrong to do so. A logical conclusion to reach if there is no difference between people and animals other than how far they’ve evolved.
You can believe there's no difference without knowing anything about evolution. The problem is an absence of theology.
Darwinism will do that.
But not even our secular scientists have a good excuse to believe in Darwinism. If they don’t care for holy writ, then they ought to care for the geological records (nature’s own witness is one reason why nobody has an excuse before God).