Doctor Carrot
Marxist Henchman
They are both propaganda weapons. There is no great fiendish conspiracy of fleets of pollsters fiddling data. All it takes is choosing a methodology that is helpful to your message.
Not really in their interest to do that, as a polling outfit anyway. Papers are one thing because they know the base they're selling to and their readership know what they're going to get. Predicting an election among other polls about general social issues and the like is a different kettle of fish. You're after hard data and your balance sheet depends on that data being accurate. If it's consistently unreliable you're toast as a business. Many polling companies have been called into question since their failures to predict accurately the last three major votes.
I get what you're saying but I think it's a bit of a red herring and not really interesting to pursue. Even if it is as big an issue you think it is you can just pick and choose your polling companies like you do with your media sources and make your own judgment.