Would you care to enlighten me on the issue with CARB-approved gas cans?

I keep reading stuff people post online where they bitch about how their “spill proof CARB-approved jerry cans” leak constantly and how they wish they could find “pre-ban” jerry can spouts.

I’ve googled around a bit and I still can’t figure out what the deal is. Were the old style (and apparently more functional) jerry can spouts banned by the California Air Resource Board? Why? And why do the approved cans apparently suck so much?