In this case it appears this crew wanted to go flying after being in the grass.
No it doesn't.
Where is your evidence for this? Where have you all arrived at this assumption from?
To get to this assumption you are assuming:
1. Captain knew they were in grass, didn't care and intended to power out. There is no such evidence of this.
2. The ground crew/headset man actually admitted to the Captain he'd pushed him into the grass and therefore do not request taxi, don't move.
There is no such evidence of this.
3. In the absence of the above happening, how is Captain to know he's in the grass without an admission from ground crew or other external reference (ATC, other aircraft, passengers in cabin). Seems the ground crew did the push, then did nothing when it went wrong and just pi$$ed off as if nothing had happened!
4. It seems that there is ATC evidence/recording of another EZY company reporting over the R/T to the Captain in question something along the lines of 'are you aware you're in the grass'.
In light of this evidence, the Captain has obviously NOT been told by anyone else with external reference that the aircraft was in fact in the grass.
So on the basis of the above, the Captain actually knew very very little other than he had been pushed back. A standard pushback for 319/320 from stands 554-561. Until someone else (company EZY) actually told him they were in the grass, how can he be blamed for thinking and doing anything other than usual, 'Request taxi'.
But of course, don't let the facts above get in the way of EZY bashing, beating each other up and a good story for the press!