SPARQL DELETE WHERE unintentionally deleting all triples from rdfstore database

Question

I'm able to retrieve a subset of my graph from rdfstore.js via the following query:

SELECT * { 
    ?subject app:rhymesWith ?object .
    FILTER (?subject = "word" || ?object = "word")
}

However, when I try to delete what I would think is the same subset of triples:

DELETE WHERE {
     ?subject app:rhymesWith ?object .
     FILTER(?subject = "word" || ?object = "word")
}

It ends up deleting all triples, even the ones that don't have the literal on either side.

Why is this happening? I want to delete the same triples returned by the select.