Actually, I agree that this poster needs to take English classes (and if her original posting represents any real effort at communicating in English, then she needs to specifically take remedial English). I fail to see how this is discrimination. The real problem is that it appears that the language capability IS there, but the effort to make her post understandable by readers is not. Thus, the post will likely be viewed as a waste of time.
Weather the poster needs to take English classes is beside the point. If you can not give a reply without making rude comments, you should just pass on replying. On the other hand, if this person was in your rental property to inquire about renting and you replied with such a response, you would most likely find yourself on the end of a discrimination suit. Most professional landlords do see how this could be understood as discrimination and the costly results. Your presumption that her post is not understandable by readers and would be viewed as a waste of time is just your opinion.