alt Hacker NewsSure, but languages and the problems we solve with them are both multifaceted, so simply pointing to one tool and saying "this is better than the one you have in your toolbox" is fine, but the plural in "zero cost abstractions" kind of implies that most or all the tools are at parity or better.
It sounds like you're saying that you consider seeing this single instance of someone writing a library with a costly abstraction to be indicative of the entire language ecosystem not fitting the paradigm. This is kind of hard to take seriously; it's not like C++ doesn't have some costly abstractions as well way more embedded into the language itself (e.g. exceptions).