Sadly it still doesn't link to the actual thread still.
Example: http://toptalkedbooks.com/books/xsKNoA/Against-Empathy-The-C...
Regarding to the low mentions count issue, it is mainly because not many people in the community talked about the same books within a month, looking at the yearly view will get better result, http://toptalkedbooks.com/hackernews/2017
Thanks