Indeed, I think it’s useful to have context for why people don’t rate/review things, such as @Biblio’s stance on rating memoirs, which is totally understandable. I also didn’t realise some people find it really difficult or burdensome to rate/review, or see it as “work”. My eyes have been opened! 
The primary reason I suggested Prompt user to rate/review and grade after marking item as finished was because for people who do rate/review/grade their items, it’s not as straightforward as it could be, as you have to do several different steps on different pages. Having everything in one place would make it more convenient, and I think this would naturally lead to more people using these features.
No one suggested pop-ups or anything intrusive, just that certain processes be made more user-friendly, which wouldn’t impact people who don’t want to rate/review/grade, so I’m not sure where these fears stem from.
