Honestly, the more I tinker with Android, the more I'm terribly disappointed in Google. I mean, around Android 2 we were all excited by the potential of a first-class big-money supported open-source OS to really shake up the industry. It had so much potential.
Now? Well, it still has a lot of potential. Even Google seems kind of embarrassed by it, compared to the Chrome brand.
It does seem bizarre they don't make any ACL on external storage. I am sure this is not a strange isolated report. This problem must have been known for years both externally and internally.
On the side note, from old news I remember Google is indeed pushing forward with Chrome-brand, specifically Chrome OS.
Because people want to take their SD card, plug it in somewhere else, and have access to their photos / videos / songs. This necessitates using FAT. That is the case for most removable media.
Now? Well, it still has a lot of potential. Even Google seems kind of embarrassed by it, compared to the Chrome brand.