Full Idea
The context-sensitivity of knowledge is inherited from one of its components, i.e. justification.
Gist of Idea
Knowledge is context-sensitive, because justification is
Source
Stewart Cohen (Contextualism Defended [2005], p.68)
Book Reference
'Contemporary Debates in Epistemology', ed/tr. Steup,M/Sosa,E [Blackwell 2005], p.68
A Reaction
I think this is exactly right - that there is nothing relative or contextual about what is actually true, or what someone believes, but knowleddge is wholly relative because it rests on shifting standards of justification.