why wouldnt it ? 
from what you describe you're returning all records from the db .. its not a complicated query .. so just trust that the code will do what its supposed to.
if you want to check the record count returned is correct .. install the mongodb Compass software and run the same query to confirm, before relying on the node completely.
[EDIT] I am more concerned that you are still using a node that hasn't been updated for more than 4 years.
I later remembered that about a month ago you were using using mongodb3 node .. and that you updated to node-red-node-mongodb instead. What happened ? why now did you install an even older one ? 
