And, yes, of course, email addresses in local languages, why the heck not? People in the world want to use their language! And yeah, even Hebrew, Tibetan, or Mongolian (in vertical script).
That comment of yours reads to me like an lazy post of a unilingual or uniscriptal cultural imperialist who really does not care about other languages.
Your attitude makes me rather angry, because Unicode is such an amazing achievement for the world, and your comment just comes off totally ignorant of that. It should be clear that combining the world's languages into a common standard is really, really difficult and will inevitably create something that is much more complex than your beloved ASCII. And it should also be clear that in such a complex standard, you cannot (a) solve all problems the first time you try, (b) you cannot try a second time, because no-one will adopt yet another such standard.
So just read those Unicode documents in order to understand. Those people really try and there are security consideration documents, and they are extended all the time. And take those new security warnings for what they are: they are problems with a complex system. It's expected. So when they get known, react calmly and figure out whether you need to fix anything.