So, for example, if you're a company with > 250 employees or > $10M revenue, and you have a Linux box pulling one open source image a week from Docker Hub, you must buy a Docker subscription for that box. And any others.
Previously, their website verbiage was focused solely on usage of Docker Desktop by enterprises.
If you are an #OpenSource maintainer and you're publishing container images on Docker Hub, they are monetizing your images, and they're doing so via a flat monthly rate regardless of consumption level. (IMHO that rate is too high, but YMMV, I guess)
This is obviously their prerogative. Really my only request/suggestion to Open Source maintainers who publish container images would be to consider also publishing them on GitHub's container registry (aka GitHub Packages) or any other registry, rather than single-sourcing with Docker Hub.