I will simply point out that, while Elecro is throwing a bit of a tantrum and should cool off, what he said was completely correct guys.
He said "No spiders are insects", which conveyed his point correctly. "Not any spider is an insect" might have been better, because there's hardly a way to misunderstand that, but you can't exactly 'correct' the already correct.
You guys just assumed he meant "No, spiders are insects."
Take this information as you will.
Though Elecro did overreact a bit.
Edit: Aw, Eksi beat me to it D: