The latter. And you're right, those == and === semantics are kind of crazy. But I think of that issue as more or less the same as the null-undefined-false-0 issue.

Also, to answer your question:

And if you know Javascript is different from Language X, and can debug the difference, why are you writing Language X and not Javascript?

... the answer, when X is Lisp, is that the benefit of the additional abstractive power is much greater than the cost of the impedance mismatch. Both sides of that equation would vary greatly depending on X, which is just a way of repeating what we've already discussed :)