At the very beginning of The Force Awakens, Kylo Ren confronts Lor San Tekka on Jakku, because the First Order has learned that
Tekka has part of a map that leads to Luke Skywalker.
In the film, Kylo Ren demonstrates on several occasions that he can
use the Force to extract information from individuals' minds.
It is also made abundantly clear that Supreme Leader Snoke is very interested in
obtaining the map, rather than simply preventing it from finding its way to the Resistance.
Finally, it is clear that Kylo Ren believes
that reading one's memory of the map is sufficient — which is why he suspends the search for BB-8 after he learns that Rey has seen the map.
So, instead of
why didn't Kylo Ren attempt to extract the information from his mind?