And, he was a damn fine author.
For those who have not read Huckleberry Finn, or who have not read it since their youth...I recommend giving it another run. I have recently and it's still astounding. He paints a portrait few could imagine.
Well, Hemmingway considered himself a writer, and at the time was probably thinking of Twain as a newspaper columnist. (Bob Roach's Plan For Circumventing A Democrat) Columnist/communist- they kinda sound alike, I guess, but he also tried his hand as a publisher. So right there are two occupations which might get him on the shit-list of some literary-minded guys.