Is Ruby or Python not suitable for iPhone or Mac app development because of speed, and any compiler that can help boost the speed? (now closed) and Why Is C# Faster Than Ruby? (closed) have both been labelled "subjective and argumentative" (nowadays "Not constructive").
One of them asks about suitability of Ruby for iPhone and the like, while the other asks why Ruby is slower than C#. The former is also from someone who mainly develops in Ruby! Neither of them are "which is better, X or Y?" or "Your language suxx0rs because of Z".
Stop being so defensive about Ruby! Just because it's fast enough for you doesn't mean it's fast enough for everyone else. And if the person is mistaken about the speed of Ruby for a particular task, create a good answer dealing with that.
If there's other, legitimate, reasons that a question is bad, please mention those reasons in the comments section of the question. For example, I voted to close the C# one because it was a duplicate.
Related question: "Why is Python so slow" shouldn't have been closed and deleted