I’m pretty sure they did this for thermals. It’s a really
common issue to resolve thermal throttling by changing your power cable from left to the right side so the power from energy draw doesn’t cause heat to dissipate internally.
The funny thing is, the last time I ran into this was at work, when a colleague mentioned they only charge on the left because of this issue. I pointed out that the original post said you should charge on the right and they were left pretty red faced after that. Clearly, they didn't have any issues with charging on either side.
If you need any more evidence, just consider the fact that the macbooks that only have ports on one side have them only on the gasp left!
Everywhere I see people talk about this issue, it points to cost saving -- what saajatjha meant
https://www.cultofmac.com/705319/macbook-pro-overheats-charg...
https://www.zdnet.com/article/can-a-simple-charging-mistake-...
https://www.ibtimes.com/why-your-macbook-pro-might-be-overhe...
https://apple.stackexchange.com/questions/363337/how-to-find...
https://www.extremetech.com/computing/309802-charging-a-macb...