We apologize for the instability of composr.app and appreciate your patience. We are working on the statistics addon and trying to find an optimal way to store and render data. Unfortunately, we have yet to find a solution that can handle the traffic (and therefore, tens of millions of statistical records) of composr.app. We're working hard on one.
#3569 - Blocking nefarious crawlers via .htaccess changes
I had a similar file years ago which appeared to work well, but this project seems way more thorough and is active so I thought I'd raise the suggestion that it might be worth a look and you'll certainly make more sense of it than me.
So essentially this is addition of a block list in the default configuration.
I probably would solve this via a tutorial to be honest, but there's a lot to read over, certainly could be some good ideas.