"Some sort of council communism is the natural form of revolutionary socialism in an industrial society."
Just like it sounds, it means that in an industrial society, the most likely form of revolution will come in the guise of socialism or communism. Which makes sense, think about it: would an industrial society have a revolution of a totalitarian dictatorship? It might get taken over by one, not a revolution by one.
"It reflects the intuitive understanding that democracy is largely a sham when the industrial system is controlled by any form of autocratic elite, whether of owners, managers, and technocrats, a 'vanguard' party, or a State bureaucracy."
This states the reality that an industrial system is controlled from the top-down, by the owners, not from the bottom up, which would be the case within the political democracy. And, when the democracy in question is a representative democracy, and the representatives can be "bought" by the industry, rather than represent the voting populace. This is largely the case in the US of A, where we are largely a plutocracy, with a veneer of democracy that is used to give the populace to a "say" in government (rather than, as it should be, steering government).