Sure, but the point is that that exact same code will throw a type error in SBCL. It at least complicates what you need to do before you can say "what implementation doesn't behave like that?".
Or is the OP's point that SBCL shouldn't exist because it's "poisoning" and "a bad thing"?
That's the problem with such FUD, can't ignore it or somebody might actually believe it, can't just say "nonsense" since that's not convincing.