Of course it's true that CLAs are not symmetrical and when you sign one, you usually give more than you gain. That's why lots of projects do not use them and are perfectly happy with a signed DCO (Developer Certificate of Origin) https://developercertificate.org/
> 2. [...] You hereby grant to [...] a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license [...]
and
> Except for the license granted herein to [...], You reserve all right, title, and interest in and to Your Contributions.
I am amazed that their S-1 includes language such as the one shown in the article.
Given that the blog post is commenting on verbiage in an official SEC filing, I will give it a pass. However, this companies lawyers are seriously misinformed (unless they are using a noncommercial license).