Agreed. The brass part is obviously higher quality, but I also wonder if it was intentionally plastic so that it would breakaway instead of damaging the battery in an event like this. If that was a design decision (not a cost decision), it would actually be a better idea to stick with the jb weld plastic part than go with brass.
It was intentionally plastic in that they were designing a molded part and chose to not have the nipples a separate part, but molded them in to save on the expense of designing and assembling a separate part.
Tesla really loves to integrate parts together - look up the "superbottle" for a previous example.
