I noticed that process hacker had been removed off some of my computers. One of them was my Windows Image that I clone from. Another was my mediabox. These are bare bones Windows 10 installs that are not normally touched by humans. So I was curious how this was happening. I did try to install it back but Windows Defender blocked it from running. I can only assume Windows Defender is what uninstalled Process Hacker. I just wanted to document this so that anyone searching for why this happened would have a place to look. I have now set Defender to "Allow" Process Hacker. I am waiting to see if it gets uninstalled again.