He is contemptuous of environmentalism and of indigenous reserves, which he sees as unfairly blocking economic development (a minority of the indigenous agree with him).
He proposed to do so by dragging it to the centre : by banging on less about the evils of immigration and the EU and embracing friendlier causes such as gay rights and environmentalism.
The HVAC engineer, for example, might value environmentalism more than money, where as the oil engineer values money more than environmentalism, which is why they chose their specific directions.
However, " green" has become associated with the general cause or movement of environmentalism – of trying to not waste energy or do anything that would harm or hurt our natural environment.