... McDonnell will use the stick rather than the carrot, compulsion rather than encouragement over china teacups. His argument is that shareholders are not the only ones entitled to company profits: the employees and the rest of society (which pays for the infrastructure used by businesses and allows them the great privilege of limited liability) also have a claim.
Capitalists will be up in arms, but they are so shortsighted they can't see their own primitive, reptilian brains are in the way. Everyone, including the capitalists, would be better off sharing the wealth more fairly and evenly.
By the way, Labour has not declared class war. What McDonnell has announced is far from class war. It's extremely modest, way too modest for my tastes.