> Later in life, Grothendieck asked for people to cease re-publishing his work, even brief excerpts.

I think Grothendeick used Mathematics as a way to rebel against/escape from the world he grew up in. It was a formal discipline that could provide concrete results, unlike the mundance political arguing and nonsense that he commonly saw elsewhere controlling the world. But, I bet as he grew older he noticed that even his very own mathematical work could be used in mundane academic political nonsense. Thus, a disenchantment with everything ensued leading to a total isolationist viewpoint.