Mark Hughes said that pilots cannot override reported weather from ATC. That is incorrectinmy view. Every company I have worked for has encouraged pilots to use their own judgement of visibility etc from the takeoff point. It is a completely different perspective to that of ATC.
Also, remember as PIC you are a qualified met observer. Perhaps, and I obviously wasn't there, they may have been better to state their plan to ATC to maintain LL til a certain point (past the cloud) and climb. Not like ATC had a lot of other departures!