OK, Dalek.
So they were pressing on in marginal VFR conditions. Who'se not done that?
Then they inadvertantly went IMC.
Even a PPL knows the drill: Get on instruments and do a 180.
I agree that these guys would likely not consider that option, so their choice was either to plug on or climb.
Looks like they did both. Stuck at it for a bit, then when it didn't brighten up, started a climb. Unluckily for them a bit too late.
Pressing on at low level, in IMC with known high ground nearby, even for a second or two is utterly foolish. They should have slowed down and climbed, or turned away, as soon as it even looked like they were going to lose VMC, and as for icing, F*ck the icing. Deal with that later- IF it happens.
Now, just to be utterly clear. I don't know and I'm not pretending to know the exact circumstances of this accident.
The legalities of the accusation against the flight crew are of zero interest to me or to them.
If ANY OTHER PILOT had done what they did, it would be an open and shut case.
Not here though!