For some reason posts or comments with some Korean characters inside aren't allowed. For example in this question it must be worked around using images How to search a Korean word made up of two or more syllables in Windows Explorer and if I edit this question Displaying Korean characters properly on a computer with English Windows XP I also get a message that says Body cannot contain "표준". When I commented with Korean characters I also get an error

I've seen this meta question Cannot ask question with Korean in it? but it's been too long ago. Shouldn't the ban be lifted off? One answer there says

The restriction on what characters are no longer allowed has been relaxed.

You should be able to post Korean characters now and the error message has been updated to be more helpful.

but I still can't use Korean characters in a post. If the spam still happens then at least count the ratio of Korean characters per post, because those spam posts contain all Korean characters