Assuming a high dimensional multi-variate search space I guess that leads to the question what the role of killing is in calculating fitness is right?

In my head the more humans / beings have known about their world the better the have survived so it makes sense intelligence would be a fitness indicator that speeds up the search algorithm. But there's no intuitive answer to why killing as many people as possible would be a fitness indicator like population wasn't a factor until recently so it's not like resource scarcity was the issue