Well, it's against their business terms that you signed when you accepted the T's & C's.But it seems completely fair to me that an account can be shared with a family member who doesn't live with the rest of the family
Basically, people shouldn't get Netflix for free as it's jacking up the prices for the rest of us!
I used to pay £9.99 a month for the family/4K plan & pricing has gone up almost 40% in less than 2 years. If people stopped sharing accounts/stealing content it wouldn't penalise those of us who use their service fairly.