LOL
LINKY
Either end of the pushmepullyou is the same.
SAE style one terminal is insulated (you want that hot)
The problem is the battery+ is hot so you want that to be the insulated side. The charger is also hot so you want to be the insulated side. The two insulated sides can't plug together so to plug them in you have reversed polarity.
In practice the battery wins and gets the insulated side hooked to the +terminal of the battery.
That works with the charger.
Bike to bike would be kablooey.
Connectors like the barrel connector have a sex. The out side of the plug and socket are ground.
The inside is + and protected with both sexes.
(I guess I should add it's the industry terminology I'm not making it up LOL)