For a very minor spoiler, know that what is happening is programmers are being killed for their code. This assumed that the bad guys knew exactly what each programmer was doing and how it could fit into their own needs, that they could just grab that code and seamlessly fit it into their own project, and of course they would record all the crimes on video for posterity was just far too gone for belief. It's hard enough to combine code from more than one programmer when they are working on the same project, let alone disparate people working on their own things. You'd have to know what that code did well enough to decide it could just plug in, which of course it never would. I went on at length about the computer end of the story, but the same problem permeates the rest of the film.
Implausibility meets unconvincing performances to create no willing suspension of disbelief.
I didn't believe the story, so I couldn't identify with it. Of course it didn't help that I couldn't identify with our hero, played by Ryan Phillippe, who looks like he'd be more at home singing with N'Sync than playing the lead in a suspense thriller. Even the actors who I usually like, such as Tim Robbins, were seemingly just phoning the whole thing in. Nothing was convincing from any of the characters. In the end, I found AntiTrust to be poorly written and portrayed, and unconvincing in its entirety.