You're absolutely right! I should have used the correct word when writing the Hacker News comment.

(lol, yes, thank you.)

This one is interesting because I have seen a fair amount of "can't be understated" on reddit also. Interesting case of linguistic drift.

In my case it was just me straight up using the wrong word by accident. Parent commenter caught it inside the edit window but I left it alone so their comment wasn't out of context. :)