I'd guess that he was earnestly invited by people who respected his contributions to software despite his social obtuseness. Then when the event was publicized,

I'd guess that he was earnestly invited by people who respected his contributions to software despite his social obtuseness. Then when the event was publicized, various "groups" got wind of it, threatened to kick up a public relations shitstorm for the institution, and the people who invited him found themselves overruled by "management".