Inaccurate meme - the white and red RCAs in composite typically don't actually carry the left and right channels - usually, the white one is L+R, meaning both the left and right channels combined into one, and the red one is L-R, the difference between the right and left channels.
This is done so that a mono television, which will only have a yellow and white port, will still be able to hear both audio channels, as opposed to having to completely miss out on one of them
It's so funny, I had the same reaction! Never quite understood it, just switched plugs until it worked. Then it got phased out and... decades later a meme brings light to my confusing childhood!
Do you have a source for this? AFAICT this is untrue. Mono audio using just the white connector exists, but this depends on configuration and does not make the red connector a difference signal.
I swear that I've seen it mentioned somewhere, but you are entirely right that I can't find a source. Maybe it was some weird device I used a long time ago? Regardless, sorry for not doing my research before posting
The video cable does a similar trick with how it supports color. This is why S-Video was superior to composite video until component came along. S-Video split the intensity and color into two signals and then component split the color further into a blue difference and a red difference. If you only wanted black and white, you didn't need to use the color signals and the image would degrade to a monochrome representation.
The composite video, with only one video signal wire, was similar to what was received over the antenna, with the broadcast signal separated from the carrier signal and the audio sub bands removed. It was the video signal with the color signal still combined. The progression from Antenna -> Composite -> S-Video -> Component -> DVI-I -> DVI-D -> HDMI -> Display Port has been an interesting one. The changes in the digital realm have been less about the image quality, the digital signal can either be read or not, and more about the bandwidth and how much data can be sent, aka resolution and framerate. Those first four transitions in particular had significant impact on the image quality.
I can confirm that everything that uses component and L/R that I have used in my life (born in 2001 in the Netherlands, so PAL) has separate L and R channels. I have confirmed this with my multimeter before.