Why are the cloud conditions well below the minima for an IMC holder?
I did say
recommended minima. With the weather given you could be flying into cloud at 400 feet, and "takeoff with less than 600' cloudbase is not recommended". Thom suggests that an average IMC holder should use considerably higher minima than those recommended.
I appreciate that the IMC covers a multitude of abilities - there's a huge difference between an IMC issued on the basis of an FAA IR and a bog-standard PPL/IMC like me - and there are IMC holders who could depart. It would probably be a bit daft for most of us.