Almost invariably, the people saying things like "If voting could change the system it would be illegal" are the same as the people bemoaning our present, opinion-poll driven political process.
Well, tough luck. You can't have it both ways. Either the voice of the people is irrelevant to those in charge, or those very same leaders are so focused on the moods of a fickle and faddish electorate that they compromise their own principles in favor of what the people say they want.
I'm not sure which alternative I find more depressing.