No I wouldn't want anyone chastising me, nor any contact with a human (that can be awkward). But I'd be happy to get an email saying "Please be aware that the book X from the science section that you borrowed earlier has been found to contain inaccurate information and has been moved to our controversial science/science fiction section".

Retractoins occur all the time in newspapera but they build on the model that people actually read the newspaper. It doesn't work when people read one article from a social media link. Fact checking and retractions should be updated to work in the age of facebook 1) Respectable media would publish retractions to facebook, saying "Please notify anyone who followed the link to reuters.com/article/123 that the article has been corrected". 2) Fact checks would do the same thing (because this is most important with less respectable media).

For this to happen obviously facebook would want to agree to annoy a fraction of their users who don't want to find their favorite links unavailable, littered with warnigs, or followed by messages that they are eating an unhealthy news diet. Hopefully they realize that this is a goal worth pursuing.