With all of todays technology, why can't someone invent a rapid charger that charges a DJI battery in 15 min instead of an Hour and a half??? What a bunch of BS. When you're out in the field away from home and want to fly fly fly for the day, you shouldn't have to waste half of your day charging batteries!!!  The cost is too much for extra batteries for alot of people??
Just my 2 cents.

Why is it automatically BS because you can't have what you want? Snowflake!

I'm not certain, but I'd assume it's due to the DJI batteries onboard chipset that protects the LiPo battery from damage caused by 'excessive' current draw or intake. Lipos prefer to be charged at or near a steady 1C to protect and prolong cell quality and integrity. Fast charging speeds up battery wear and can, in some cases, cause battery damage. DJI don't want to replace your damaged batteries under warranty or be dealing with lawsuits due to their drones falling out the sky because of damaged power packs.