The reasons listed are grouped as "code review" or "stack overflow", places where I would usually want to help, and having a list of pre-written mistakes to cop

The reasons listed are grouped as "code review" or "stack overflow", places where I would usually want to help, and having a list of pre-written mistakes to copy-paste might be usefull. But the first half of the webpage only talk about communities in general, so I first assumed this was meant to be used on places like hackernews and reddit, places where downvotes most of the time mean: "you are an idiot/troll, I'm downvoting this to save other people from having to read this garbage." A situation where I really don't want to help the poster...