In Altcoins board all announcements must be in English. If your ANN was written in Vietnamese, then it's normal thing that your thread was deleted. Example which you posted is also breaking forum rules, it should be deleted. Mods probably just didn't noticed it, this is why this thread isn't deleted.
But how I can post review in vietnamese, It's no way to do that???(((
Hilariousandco already explained it - if you don't have local board you can't post ICO ANN's in your language.
It's not likely that Vietnam will get local board in near future, thanks to spammers and abusers from your country.