It's the mixing of tenses that infuriates me, because "why'd" means why did. So either change it to "why do" or change "you're" to "you were".
The "why'd" over here means all of the ones Paul said really. It's a shorthand/colloquial way of saying "why did", "why would" or "why do" all separately.
Technically wrong, but it's just the evolution of it and the informal nature of the phrase over here.