You're right that it's not a vulnerability of Ethereum. It's representative of a weakness of Ethereum and it's language which makes mistakes like this bug a lot

You're right that it's not a vulnerability of Ethereum. It's representative of a weakness of Ethereum and it's language which makes mistakes like this bug a lot more prevalent. It's sort of how like a "use after free" bug in a program written in a non-GC'd language isn't a vulnerability of the language itself. Languages encourage or discourage (or even eliminate) lasses of bugs based on their design. Etherum's is particularly bad in this regard.