Philosophically a good point, but in reality, that is a bad analogy. Your local gas station won't cut you off if you drive for Uber. The guy who built your house won't tear it down if you rent it out. But your ISP can, and will, disconnect you.
There is a significant difference between freely using something you own. vs changing how you use a service that you do not own, and have signed contracts specifying terms of use.
Are you sure that your ISP can really figure that you are sharing internet with others at their end ?
Even if they do, legally speaking, will you sharing the internet connection on your name with your flatmate / family members would amount to breach of contract ? In all likelihood, your flatmate shares the cost of the internet with you. Isnt this case is exactly the same, somebody else using your internet & helping you offset some of your cost. Am I missing something here ?
Only if more than 1 provider is available in your area. With my ISP, sharing with the public is not allowed. As such, any torrenting that happens I am responsible for. The only other provider we have is dial up, which I don't consider an alternative.