Translation:A vegetarian who eats meat is not a vegetarian.
In practice, the use of relative pronouns is extremely flexible, especially regarding ‘that’: it is often used for both human and non-human referents and often also in non-restrictive relative clauses, where in theory only which (non-human) or who (human) should be used.
Some argue that only ‘who’ should be used to refer to humans, regardless of the type of sentence. That is by no means a universal rule, though. If anything, it could be considered a suggestion. At any rate, always using ‘who’ for human referents is at least allowed, if not always recommended.
As far as the usage of ‘that’ in non-restrictive relative clauses (those that simply add new information about the antecedent, like ‘my mom, who is 50, is very nice’ or ‘dogs, which are notoriously obedient, make for good pets’), as opposed to restrictive relative clauses (restricting the statement to only the group of referents that satisfy the requirement, like ‘moms that/who are older than 50 are nice’ or ‘dogs that/which obey their owners make for good pets’), I would discourage that. While possibly accepted informally, it is at the very least nonstandard.
In American English, that is used to introduce restrictive clauses, and which introduces nonrestrictive clauses.
- The lamp that Aunt Betsy gave me is on the bedside table.
- The lamp, which was given to me by Aunt Betsy, is on the bedside table.
In British English, it is often acceptable to substitute which in restrictive clauses.
- The lamp which Aunt Betsy gave me is on the bedside table.
Recently received the following email, for any and all interested:
You suggested “A vegetarian that eats meat is no vegetarian.” as a translation for “Ein Vegetarier, der Fleisch isst, ist kein Vegetarier.” We now accept this translation. :)
Thanks for the contribution, please keep it up!