Why would I need to? Nobody volunteered. In the analogy, you found something on a shelf somewhere and decided to depend on it. The person who put it on the shelf never agreed to support you in that endeavor.
Are different states. 'Maintenance' is not work-free or effortless, so the second sentence is explicitly volunteering to do some non-zero amount of work, right?
I don't see how it can be read any other way, you either have to argue that maintenance isn't work, or that "I am the maintainer" is not volunteering oneself into the role of doing that work.
You understand this is the opposite of your example before right?
It's like a business asking for volunteers, you saying you will, then the business demanding that you turn up when it suits them and you not being allowed to say "no"
If I have a garden in my yard and I say “I am the gardener of this garden”, what commitment have I made to you, a third party who just happened to be within earshot, about how much time I will spend working on the garden?
We're not talking about someone who "just happens to be within earshot" of something that is inside your private garden and not open to the public.
If you put a note on the public noticeboard saying "I have planted some things in this area of the public commons and I am the maintainer them" can you defend the idea that you are not voluntarily offering to maintain something?