So I thought it was a reasonable criticism of an overly broad or at least very ambiguous assertion, regardless of its motivation. It’s quite common for the best arguments against an argument to come from people who are hostile to it for whatever reason. More carefully defining the scope of things where we would expect COBOL to get top performance marks would make the conversation far more informative and productive.
As for assembly, there is now a broad class of problems for which CPU assembly is far from the fastest solution, because GPUs are faster. Even on the CPU, there is a widespread (but usually false) belief that compilers beat expert assembly programming. So perhaps to you it's a vacuously true statement that adds no useful information, I read it as rebutting a belief many readers may really have (though, unfortunately, only as a bare assertion.)
I think it's unreasonable to expect every comment about every bit of technology, old or new, discussed on HN to come with pages of preamble, caveats and definitions of terms.
The question ‘fastest at what’ is right there in the original quote - processing. Assembly isn’t commonly considered a ‘processing language’ and in the context processing is a term of art for the kind of batch processing tasks cobol was designed for.
Even that aside, we all ‘know’ assembly is the fastest. It’s a given. Nitpicking comments like that betrays a hostile attitude and lack of generosity of spirit. We shouldn’t have to post pages if caveats and justifications and hedging for a comment like that.
Attacks like this come across as intellectual grandstanding and aren’t actually contributing anything of value.