You are correct, but to someone new, the phrase sounds like an absolute and probably discourages them from ever trying. A great blog post about this phenomenon is https://soatok.blog/2021/03/04/no-gates-no-keepers/ .

For my part, I've met people who have told me to not even try because I need to get a PhD before I even implement crypto. Not design crypto; implement crypto.

So while you are correct that it is the mainstream interpretation, that's not how it looks from the outside.