Not everyone with the knowledge to identify this mistake is in a position to personally correct it. Do you have the time and resources to personally build a browser from scratch? No? Why do you assume a random commenter does?
It doesn’t change the fact that Rust is similarly performant and much safer and will thus be faster to develop and less bug-prone. It’s not a difficult assessment to make. If you want to explain why they’re wrong you can talk about the issue on its merits, but you didn’t choose to, presumably because you can’t.