If even translators sometimes make mistakes in languages that share the same alphabet, imagine how difficult it must be for people who use hanzi to understand us?
It must be quite annoying to receive messages in a language you don't understand saying strange things to you. It's better to just try your luck with Google Translate if you really need help, that way, at least it shows that you're trying to communicate and not just being lazy. So yeah, I don't blame them for having those DNIs, it´s a warning, so you can't blame them for a surprise block.
First, for translating between English and Chinese, my experience suggests it's better to use LLM (like Gemini or Deepseek, which are free). They can provide more accurate translations for slang and internet terms.
If you are worried about translation issues, a good method is to send both the original text and the translation together to avoid ambiguity. You can also use different translation software and LLM to translate the result back into the original language to check for any confusion. (This is what I do myself: I use Gemini to translate, then use Deepseek and Google Translate to translate it back to check for any ambiguity).
Furthermore, for me personally, if someone sends me a message in a language I don't understand, I would first request that they use English or another language I know. At the very least, I would leave a message saying, "对不起,看不懂" (Sorry, I don't understand,)before blocking them, rather than leaving them to guess what I'm thinking.