Let's (easily) debunk each of your sources to demonstrate their complete irrelevance to this topic:

- The Mass Killings article you post describes mass shootings, which are a specific type of homicide with a narrow definition. Homicides overall are down dramatically since the early 1990s. Mass shootings are aided by poor gun control policies and mass availability of guns in the United States. Mass shootings are not prevalent in developed countries that are not the United States in significant numbers.

- The Violent Crime article you've cited only talks about the past two consecutive years, not the decade-long time period cited by the religious affiliation trends in this article.

- Homeless populations probably aren't sampled in this phone survey, so the homelessness rate can't be correlated with the information given here.

Your weak correlation to religion is entirely debunked by choosing just about any Western/Northern European country, or much of Asia like China, South Korea, and Japan, and noticing that their religious affiliation numbers are far lower than the US has ever been, along with their violent crime rate.

What do Christian churches do? They certainly don't pay property taxes, so they don't fund public schools, police, or mental health services, like a normal business or resident would if they occupied the property.