You have made a logical fallacy sometimes known as the is-ought fallacy or is-ought problem.
The key point is that the parent is stating that things ought to work a certain way. While your statement that things are a certain way may be true, it is actually a non sequitur in relation to the ought proposal.
If you wish to make a cogent argument you'll need to address the ought section of his argument or connect your "is" statement to be no longer orthogonal.
Unfortunately, I have to agree with this, as the author of the post stated, "I work as a entertainment industry consultant, and depend on cloud services such as Dropbox, Simplenote, Google Apps, and Google Docs for day to day work. I use streaming online services such as Netflix, Xbox Live, Playstation Network, and Pandora every day for both work and play."
Okay, so get a business class account, and Comcast will not throw a fit when you completely saturate your residential neighborhood upload link.
Unfortunately, it is a 2-year minimum contract with an install fee over $200. However, sign up for a 4-year contract and installation is waived.
He could also have two cable modems, one residential account in the roommate's name and a business account in his business's name.
While I agree that he should pay for a commercial plan if he has a commercial use case, having one provider is certainly not the way the market should work.
Why is using more than 250GB of data a commercial use case? The author thinks his personal interests in photography and music are what topped the cap. I doubt Google Docs and his other work services would even show up on his bandwidth compared to Netflix and XBox Live.
Consumers shouldn't have to upgrade to a business plan, paying for business-class support, a static IP, and other features they don't need. Comcast would probably end up making more money and saving a lot of face if they had a plan with sane limits for people who live on digital media.
The key point is that the parent is stating that things ought to work a certain way. While your statement that things are a certain way may be true, it is actually a non sequitur in relation to the ought proposal.
If you wish to make a cogent argument you'll need to address the ought section of his argument or connect your "is" statement to be no longer orthogonal.