Ok, I hate to do this, because I totally agree with your point, but Ted is really not related to Skakel. Skakel is related to Robert's wife, Ethel. So, yes, Robert's kids are related. Ted and kids are not... not any more than my husband is related to his brother's wife's family, or I am related to my brother's wife's family.
A Kennedy is a Kennedy is a Kennedy (doesn’t matter what the last name is). They are so inbred nobody can tell them apart anyway.
When you are a Kennedy relative; you are considered a Kennedy.