The problem is that use of unusual Unicode characters represents memes, there are constantly new ones and it would be hard for any screenreader to keep up with

The problem is that use of unusual Unicode characters represents memes, there are constantly new ones and it would be hard for any screenreader to keep up with new stuff. And there are plenty of imaginative use of letters from Indian scripts, from hieroglyphics, etc. where the screenreader can’t be expected to recognize what is intended as easily as a human being would.