No it is not impossible. English is quite easy (in most cases)no matter what your native language is. It might take some people more time than others to learn it, but that doesn't make it difficult. Try learning Mandarin (category 5) in comparison and get back to me.
It isn't impossible, but it isn't as easy as you think it is. English actually has a lot of weird nuances and strangeness that can be rather difficult to get a hang of. Compared to other languages such as any dialect of Chinese, english is fairly easy. However, for people who are learning english, if their native language isn't a Romance or Germanic language, they will find that English is hard to learn.
But even so, perfect english on this forum isn't necessary, just good enough that it is understandable. Broken english is not tolerable, especially because nearly everything on this forum involves someone's money and when dealing with money, good communication is key.
issue is within the native speakers (some not everybody): these must respect other nationalitys. i come from country where if your speech poor people say good job, you try speech. on btt often people say haha you try speech now go home. not friendly or serious.
We don't care about other people's nationalities. The country you come from doesn't matter here. What matters is that you can communicate well with other people on this forum. People will tell you to leave if you are posting with broken english because it is not good communication and no one wants to do anything which will risk another person's money. If you continue to post with broken english even after being told that you need to learn to write better, then people will start getting very annoyed.