The only reason Harrelson was doing an AMA was to promote the movie Rampart, which Roger Ebert claims was a great movie but Reddit didn't give two shits about. Literally the first actual question posted on the AMA was about Harrelson's estranged contract killer father, and then things only got worse. Even though Reddit asked a whole bunch of actually decent questions pertaining to Harrelson's acting career, the first thing he felt deserved an answer was about the time he apparently took the virginity of a drunk 17-year-old girl. Allegedly.
There's a chance that Reddit might've let this go if he hadn't added that last sentence. By asking Reddit to focus on something, in this case his movie, it became clear that this was just a PR stunt, and they tore into him like a puppy into a squeaky toy. There was to be no mercy.
Finally, some Redditors noticed a couple grammatical mistakes indicating that this wasn't even Woody Harrelson; it was a really shitty publicist who couldn't be bothered to keep "Woody's" responses in the first-person with 100 percent consistency. Once this discovery spread throughout the AMA, it was a total shitshow. People started directing comments directly to that publicist, who I can only imagine lied straight to Harrelson's face about how great the AMA went and probably had to bribe Roger Ebert for that review.