The description frequently mentions they are gross. Why?
It’s just blood.
Do any traits (such as psychopath) influence descriptions of such things?
Is the player character a sissy by default? 
vacutainer with blood is realy gross for character because its human (so you need to be canibal or psyhopath) and its not enjoyable food too
zombie blood is not human but its not enjoyable
From what I recall, the odds are good that you might puke from overingesting blood, even if you can ignore how unappetizing it would be to most people.
zombie food give food poisoning and poison just like tainted meat if my memory is well