Fisherman
These phrases do not relate to “abstain” because abstain deals with consumption. Or conduct involving pleasure.
If you're asserting that eating (or possibly drinking) of blood should be understood from the context of the Decree, then I'm in complete agreement.
Abstain and its synonyms (refrain, forbear, etc.) negate action. The fundamental meaning is to keep or prevent oneself from doing or saying something. (I'm quoting the American Heritage Dictionary word for word)
"Although the argument was intense, the couple abstained from hateful words"
This is a perfectly legitimate use of the word. The action, though unstated, is derived from the context
"Her obstetrician said, 'Pregnant women should abstain from alcohol.'"
"His dermatologist said, 'Persons with sensitive skin should abstain from alcohol.'"
Even though both doctors have said, "abstain from alcohol" we would not automatically understand them to be talking about the same thing. While we would understand the former to be a reference to alcoholic beverages, we would understand the latter to be a reference to the topical application of alcohol.
English, of course, is not the language the bible was written it, which is why grammar and context are crucial.