Possible idea for a new sub forum.

[Steve Ashton]

While you are correct that the use of the phrase is most commonly attributed to Justice Stewart, he was not the first to use the reasoning (excuse).
Another example is from the second Edward R. Murrow "See it now" episode when Sen. MacCarthy's popularity was waning, Mr. Murrow was publicly challenging Sen. MacCarthy to show proof of his accusations of communist spies and blackmailed homosexuals infiltration of the US State Dept. Mr. Murrow asked - "How do you know?" The response was "I'll know them when I see them, and I'll call it as I see it."
Both Justice Stewart's judgment and Sen.MacCarthy's "MacCarthyism" are often used in debate and rhetoric to illustrate instances where one person's, personal outlook, are used to illustrate the fallacy of "moral instinct".