I'd have to go along with that as well. The solution to problems is often to get rid of things one can't comprehend. To say that religious wars and killings weren't a reality would be nonsense. So if we "got rid of religion" which isn't likely we'll likely just continue as we are with a far deadlier thing, politics. The majority of people who died in war was for that. WW2, WW1, Vietnam, even Iraq and Afghanistan. Politics, power and wealth still exist. Machete killings in Africa are tribal, on and on.
The bottom line is that humans are consummate executioners and we evolved to be just that. We aren't smarter because it's better, we're better thinkers to be better killers. We are the planetary hyper predator even on ourselves because we were born that way. As social creatures, humans will follow politicians as much as any god and because the former is seen doesn't make them good. We're the walking nightmare of any intelligent creature who finds self-extinction anathema. The old Roman Catholic church, with their use of God for power and wealth while not being Christ-like isn't different from the pogroms of Mao or Stalin or persecution of anyone. It's who we are as a species, murderous cavemen who survived a mass extinction 70k years which knocked us back to perhaps 30K individuals who came out "better" with increased social skills and intelligence. Now Slow and his politicians want to finish what the Toba supervolcano failed to do tens of thousands of years ago.
We will always find a reason to hate, to follow, and kill as a species. It takes effort to resist that which we tend to embrace.