I understand your concern. I wouldn’t be criticising their spelling in the main body of the post, but at the very least they should be spell checking the title. An occasional typo is usually forgiving but if the Lemmy feed is showing a post with many spelling mistakes it’s not going to go down well.
Learning spelling and ensuring it is correct is part of learning a language.
If I was posting in a Chinese forum, I would be very careful to ensure the Chinese characters are correct. Differences in minor radicals can make all the difference, e.g. 慢 and 漫 are distinctively different words. It’s a different kind of spell checking.