The claim the pilot is 100% responsible is just more Malaysian BS.
They do not have a shred of evidence that would withstand legal examination that the pilot was responsible for the loss - but he was a supporter of the Opposition Leader, so he can become a very convenient scapegoat.
This is standard practice in a corrupt country, where to eliminate the Opposition Leader, you trump up some "indecency" charges, and jail him for 5 yrs to get him out of the way.
The Malaysian police claim the pilot is the "prime suspect" because he made no "social or professional future plans".
If that single observation makes one a "prime suspect" in an aircraft hijacking/loss - then 10,000 other pilots around the world, are also "prime suspects" for future hijackings/aircraft losses.