My argument is that "open source principles" do not suggest anything about how the maintainers have to handle input from users.

Open source principles have to do with the source being available and users being able to access/use/modify the source. Chrome is an open source project.

To try to expand "open source principles" to suggest that if the guiding entity is a corporation and they have a heavy hand in how they steer their own project, they're not meeting those principles, is just incorrect.

The average open source project is run by a person or group with a set of goals/intentions for the project, and they make decisions about the project based on those goals. That includes sometimes taking input from users and sometimes ignoring it.