I think this is too harsh. Out of the languages mentioned in the article, at least one (JavaScript) has no builtin lookup-or-throw method, and another (Ruby) r

I think this is too harsh. Out of the languages mentioned in the article, at least one (JavaScript) has no builtin lookup-or-throw method, and another (Ruby) requires a method call that's significantly uglier than the normal [] syntax, slightly discouraging its use. I don't know enough about the others (besides Python) to speak for them. In comparison, Go's multiple-return lookup thingy might be less natural/obvious than straight usage of foo[bar], but not by much.