They exist so that you can continue to use hashicorp tools in your business for free and look at/change their source code like you would any other software.
The one restriction is that you can't compete with their hosted services using their software. Which 99% of people who use their software have zero interest in.
The "it's not fair! it's not real open source!" narrative is pumped up by companies like Amazon that feel entitled to use their monopoly power to leech value from these companies by selling paid versions of their products.
No, Open Source has always required that usage be unrestricted (Either Freedom 0 or OSD/DFSG points 5 and 6). Allowing any restrictions on usage tends to get political, as people use the license to push their specific issue, making it much harder to share and use code without issues.
So requiring that anyone that runs your code and tries to publish a paper can only do with your approval (which is a real license that exist) is fine also? Saying "anyone can use this however they want" is much easier to check for that coming up with rules (and licenses) that allow for the BSL but not for the above academic licenses.
It literally is not, and they only exist in order to not be.