2K intentionally gives 4:3 screens more visual information
Actually, the game gives wide screens
more visual information, because the "game makes use of the full screen resolution, and does not crop or stretch a lower resolution image into a wide screen one." Wide screens have more pixels. More pixels = more visual information. It is simply that the information is in the form of greater resolution and a larger, clearer picture in the "business" part of the display where the real action occurs.
Part of the problem seems to be that some people are defining "wide screen support" based not upon how well the resolution of the screen is employed in support of the artistic and gameplay goals of a game's designers, but instead by a nonsensical comparison of how much stuff you see on the sides compared to a 4:3 display. I had to laugh at one exchange with one of the game's developers, where somebody asked him if the game was going to be "vert-" and he obviously didn't know what the questioner was talking about--not surprisingly, because it is such a foolish way to think about widescreen support that it makes no sense.
From the point of view of a designer, the game should provide the optimum game experience possible on a particular system. For a game such as Bioshock, whether or not you can see what is sneaking up on your sides is crucial; how much of the floor, ceiling, or your own wrist that you see is unimportant. So the designers made the decision to effectively "letterbox" the 4:3 display, reducing the vertical size and resolution of the part of the image where all the real occurs in order to fit it onto a narrower screen. For a film, this would have required letterboxing--black bars above and below the image. But since this is a computer, the designers were able to fill in that space with visual data above and below that was not considered important enough to show on a widescreen display--which at least prevents problems of burn-in on CRT and plasma screens, and helps to disguise the fact that 4:3 screen owners are getting shortchanged on the part of the image that really matters.
But now, widescreen owners, convinced that their wider screen entitles them to see more "stuff" on the sides than their benighted 4:3 brethren, are demanding a wider FOV. Of course, the current FOV is the one designed and play tested by the designers, and the complainers mostly haven't even played the game to any extent. But perhaps the developers will give in to the demand and release a "wide-FOV" patch, and "widescreen=more stuff on the sides" zealots will play it in that mode, happy that they are getting what they think of as a "true" (i.e. more FOV than 4:3) widescreen image, and blissfully unaware that they are actually getting a degraded game experience.