You are correct. Depending on what the person is trying to say, the first sentence should be "Why do you do this?" or "Why are you doing this?" or "Why did you do this?" (past tense). Second sentence should be "Why do you have to do this?" depending on the tense. Often in fast English, native speakers might say the last sentence like "Why'd you have to do this?" which may sound the same as "Why you have to do this?", especially for certain accents.