The error you got hedges its bet a bit:
We aren't accusing you of spamming the site, but rather letting you know that it looks like you are spamming. That's because we've seen inordinate number of spam attempts consisting largely of Chinese characters. On a site about Chinese, such as where you found the link, we obviously can't block Chinese characters. But for most of the rest of the network it's a strong bet that people using Chinese characters are attempting to post spam.
Just to be clear, this is a pretty rotten solution. Blocking an entire block of Unicode characters isn't something we like doing. But the alternative would be to block huge swaths of IP addresses. Inasmuch as it's possible to work around the block to post legitimate content and impossible to post the payload the spammers seem interested in propagating, it's been a worthwhile tradeoff.
That said, we could probably reword the "Would you mind doing that elsewhere instead?" sentence. It's a bit presumptive when a non-spammer posts something that tangentially looks like spam. Any suggestions?