Oppenheimer "never regretted his role as the chief architect of the bomb. . . .
"Oppenheimer continued for the rest of his life to be proud of his achievement at Los Alamos. We know this because he protested vigorously in 1964 when the German playwright Heinar Kipphardt wrote a play portraying him as a tragic hero regretting his actions. Oppenheimer threatened to sue Kipphardt and the producers of the play if they continued to misrepresent him. The producers cut out the offending passages from the play, and the case never went to court. Oppenheimer continued to block later attempts to produce the play in London and New York."
Freeman Dyson, "Oppenheimer: the shape of genius," New York review of books 60, no. 13 (August 15, 2013): 19 (18-19). So in quoting Vishnu, Oppenheimer was in no way second-guessing himself.