There have been a lot of articles recently about the content of Grand Theft Auto V, and how it reflects on, approves of, encourages and/or influences the behaviour of its audience. A torture scene is being called out as particularly problematic.
I've still not played the game - I hope to borrow a copy from someone at work eventually, but I'm not going to buy, implicitly supporting, Dan Houser's… output - but there's certainly a question about how necessary it is to portray torture in a piece of entertainment, and how necessary it is that the player participates in it.
One of the main problems with this conversation in the context of Grand Theft Auto as a series is that it's difficult to take it seriously. The previous games have always positioned themselves as parodies of their cinematic forebears (best exemplified by Vice City's wholesale appropriation of the plot of Scarface). But it's never been a series with a message; indeed it seems like the developers encourage people to shrug any controversy off with "it's just a silly game".
In the context of Spec Ops: The Line, you can make a point about the willingness of players to go along with objectives unquestioningly, no matter the outcome - in that instant, it's essential to the theme that the player takes action. It's much harder to communicate a point about the consequences of your actions in a game like GTA because the whole thing is a celebration of consequence-free activity.
The minor penalties visited on you for breaking the law - which only come after an exhilarating car chase, trying to outwit and escape the police, and even then only if you fail to get away - are far from prohibitive. You lose some money and your weapons, but you always come back with a clean slate.
With that in mind, it's difficult to see what point, if any, Rockstar are trying to make by including a torture scene. It doesn't seem to serve any narrative purpose - in fact a number of comments online suggest it's actually out of character for the player's avatar to go along with it - and it can't, by the nature of GTA itself, have any long-term implications for the player or characters.
The only possible conclusion is that it was included for people to talk about, to drive up controversy. Which is hardly a first for the series, but the original Grand Theft Auto's playground wasn't trying as hard as Rockstar's latest to take a place alongside mature cinema.