You are paying for 4 screens or streams limited to members of your household. By using their service you agree to their TOS which defines an account being limited to a household.
A Netflix account is meant to be shared with people who live in the same location with the account owner.
help.netflix.com
If you are sharing your account with someone outside of your household, as defined in the TOS, you are in violation and stealing.
What is your problem with that? Pretty simple stuff, you might not like it but if you want their service and content you play by the rules or you steal from them.