it would honestly be everyone's fault.
A) The user for not having decent anti-virus which would more likely instantly detect the key logger before it executed. If you don't believe you need anti-virus then you're a fool.
B) The company like asmit stated for recommending the program.
@noblem hacking isn't that simple. Most people who are hacked, tapped, or infected will never even know it's happening. This is how really complex operations done by the NSA and white/black hat hackers are done.