The average user doesn't even recognize that running a website literally cost electricity that must be paid for. Who pays for it? Who will carry the boats?
Running a retail store also has costs associated with it, including, yes, electricity.
Yet if I walk into a store and leave without buying anything, do I feel like I owe the store owner anything?
No. That's not how that works, nor is that how it should work.
For residential usage, unless you're in an apartment tower where all your neighbors are software engineers and you're all behind a CGNAT, you can still do a pull here and there for learning and other hobbyist purposes, which for Docker is a marketing expense to encourage uptake in commercial settings.
If you're in an office, you have an employer, and you're using the registry for commercial purposes, you should be paying to help keep your dependencies running. If you don't expect your power plant to give you electricity for free, why would you expect a commercial company to give you containers for free?
10 per hour is slightly lower than 100 per 6 hours, but not in any meaningful way from a bandwidth perspective, especially since image size isn't factored into these rate limits in any way.
If bandwidth is the real concern, why change to a more inconvenient time period for the rate limit rather than just lowering the existing rate limit to 60 per 6 hours?