Robert Steele of the open everything manifesto writes(

Open Data without open everything else is simply a gift to vendors of
proprietary hardware and software and does NOT further the commons or the
public interest to the fullest extent possible
I appreciate this idea and I used to subscribe to the open everything together idea, but I have changed my mind recently.

I prepared an presentation on open everything for the presentation at the NEKLS innovation day in Topeka recently

I would say that a project needs to use open interfaces that allows new users coming from outside of the free/libre open source world to connect and use them.  This is for the simple fact of numbers, a project needs users to be successful and most users are using proprietary software.

Even if the android software might be based on linux, and it is the most popular device currently ( ) I dont think you can really consider it to be free software environment ( ) . Even then we still need to keep open access to all parts of the stack and allow users from to use open standards to communicate with our project.

Each layer of the open everything cake can be seen in isolation and must be viable. The open data part of Openstreetmap cannot limit it’s usage to only one client for example, the servers running it also use rest interfaces via an API.
My argument is due to my experience with promoting open everything, culture etc in places like Kansas and Kosovo. Openstreetmap is one project that it would be difficult to dictate only open source clients operating system for usage. Mozilla is another project where even the developers use windows and the artists use adobe, I don’t agree with it but it is how it is. Wikipedia would be much smaller if only Linux users were allowed to edit.

So I encourage you to get new people involved, if they be comfortable using windows or mac or whatever, it should be important to first sell your project for it’s value, make it accessible and available and useful, and also explain your philosophy of free/libre openness to them, let them make a choice, let them learn about it themselves and maybe if they like one part of the freedom cake they will also try out a different part.