alt Hacker News> long enough ago that he had forgotten he'd named it that
Actually sounds a lot like "that was the default name but now that everyone's making a big deal about it I'm assuming I must have named it that". I wouldn't assume that this "confession" means that reddit's theory is at all incorrect.
Witnesses are terribly inaccurate sources of information, unfortunately.
(Not to say the alternative also couldn't be the case)
Renaming a Bluetooth device like a speaker permanently for everyone (as opposed to a nickname you give it in your phone or whatever) is difficult if possible at all and usually requires firmware or hardware changes, unless the option is given by the device or its companion app (which is very rare).
So your assumption seems the most likely. I highly doubt a 16 year old kid is firmware hacking a cheap speaker just to rename it for a "joke"