Technology

This is not true. The GPL does not force anyone to give up their code, unless they distribute it. From the "Definitions" section:

A “covered work” means either the unmodified Program or a work based on the Program.

And

To “convey” a work means any kind of propagation that enables other parties to make or receive copies. Mere interaction with a user through a computer network, with no transfer of a copy, is not conveying.

And from the "Basic Permissions" section:

You may make, run and propagate covered works that you do not convey, without conditions so long as your license otherwise remains in force. You may convey covered works to others for the sole purpose of having them make modifications exclusively for you, or provide you with facilities for running those works, provided that you comply with the terms of this License in conveying all material for which you do not control copyright. Those thus making or running the covered works for you must do so exclusively on your behalf, under your direction and control, on terms that prohibit them from making any copies of your copyrighted material outside their relationship with you.

Conveying under any other circumstances is permitted solely under the conditions stated below. Sublicensing is not allowed; section 10 makes it unnecessary.

Under the terms of the GPL, the owner can revoke your access for any violation of the license, and at their discretion, they can make that revocation permanent. The GPL does not guarantee equal treatment - an author can punish one person harshly, and another not at all. It still comes down to the author. Yes, there is a small barrier in that you have to find a violation, but if you look hard enough, you can probably find a violation - especially in large projects using libraries distributed under multiple different licenses.

the FUTO license can revoke the license just because Rossmann says so. It is a mechanism to keep Rossmann the owner of everything that spawns from the code of the app and being the only one who can make money from it. If Rossmann doesn’t like someone who wants to redistributes the app, he can immediately revoke their license.

Quoting from my comment here:

They’re just trying to prevent a company from making money off the free labor of the authors. It’s the same issue that has plagued other projects, such as Elastic Search, which ultimately led it to change licenses. And it’s why MariaDB created the BSL, which they and other companies have adopted (very similar terms here - source free to use for non-commercial purposes).

If the hangup is specifically that they can change the terms, or revoke rights altogether, the other licenses also allow for that - that’s how these projects are changing licenses at all, and it happens quite a bit. I have personally contributed to projects that were GPL, and then went Apache.

only one who can make money from it

This is not true. You can make and sell plugins, you could offer support, you could sell your services as a code auditor/security expert... anything other than selling the code you didn't write. On top of that, in practice, this isn't different from anything else - most contributors to open source projects don't profit from them, unless they work for the organization that owns the project. When the non-owners do profit, it's usually big companies and results in the license changes I've described above.

A user that doesn't care about licensing is typically called a pirate.

The license literally does not govern the usage of the app. Here's the first line:

This license grants you the rights, and only the rights, set out below in respect of the source code provided.

Read the entire license (it's only 32 lines), and you won't find anything related to using the product, only the code.

This license should only be scary to developers, who might build on the project, and then have it taken away. As a user, your concerns are different, and this license vs the GPL, or any other FOSS, or even source available license, are more-or-less the same. As a user, your primary concerns are probably going to be related to the security and privacy related aspects, and as long as you have access to the source, you can audit it and ensure it meets your standards. If they choose to revoke access to the code, as a user, you're in the same boat you described - don't take new versions because you can't audit them, but you can stay on the old version. They can't revoke that access with this license, because again, this license literally does not govern usage of the product.