I think this is a really great example of how even a simple phrase can detract from a whole argument[1]. While reading the paragraph in whole, which I included below[2], makes it clear that the blog author does respect the WebAssembly team it is important to remember to be very careful with words when being critical of work. We all inject a bit of ourselves into our work, so criticism is often taken very personally. So err on the side of grace and assume the creator knows as much as you do, if not more.

[1]: I understand that the comment author has other concerns besides the phrasing, but I'm only focusing on the phrasing right now.

[2]: The developers of the WebAssembly spec aren’t dumb. For the most part, it’s an extremely well-designed specification. However, they are weighed down by WebAssembly’s legacy. WebAssembly started out not as a bytecode, but more like a simplified binary representation for asm.js. Essentially it was originally designed to be source code, like JavaScript. It would be a more-efficient representation thereof but it still wasn’t a proper virtual machine instruction set. Then, it became a register machine, and only at the last minute did it switch to stack-based encoding for the operators. At that point, concepts like locals were quite entrenched in the spec. Not only that, but for the most part the WebAssembly specification team were flying blind. No streaming compiler had yet been built, hell, no compiler had yet been built. It wasn’t clear that having locals would be problematic - after all, C gets by just fine using local variables that the compiler constructs the SSA graph for.

In an engineering discipline, asserting that someone is 'flying blind' could very, very easily be taken as offensive. Knowing what's going on and why is so fundamental to 'good engineering' practice that you basically are calling the people ethical failures. 'Impugn' is a perfectly reasonable word for how someone might react to such an aspersion.

Maybe in the future don't accuse engineers of 'flying blind' if you aren't inviting return fire.

From context there was a lot of conjecture going on, but the big challenge with building something new is what order to build the bits in to give you the most useful information fastest. As the number of people goes above 2 the odds that everyone agrees or that 'everyone' is right drop rapidly toward zero. You do the best you can, and hope it's good enough that you still have time to react to the worst of the decisions you made earlier. But it's not 'flying blind'.

Wow, not the kind of engineering room I'd want to be in. You have to be able to make claims that the other party does not have a complete picture of the situation, and an external critic is indeed going to be vulnerable to the same criticism.

Maybe you would have a point if it were a Linus-style "only a fucking idiot would" rant. But responding to a sincere attempt to defend a design decision as if it were an insult is some prima donna behavior.