It's obvious to anyone who has shipped almost anything that costs are different by size and weight and scale.The discriminatory pricing refers to the client, not to the shipped goods.
Pricing for different goods by type, size and height is appropriate because of the different resources needed to ship those goods. More fuel and studier cars are needed to move iron loads vs a load of pillows. Moving coal requires open-topped coal cars while moving ice-cream requires refrigerated cars, etc.
Telecoms are in the business of moving bits. If they want to charge more to move a gigabyte of video data than they do to charge a gigabyte of text data, or if they want to offer slower speeds for a gigabyte of torrent data vs a gigabyte of FTP data, I think they should better explain how the different types of data justify the different charges.