As someone who works as both a maintainer and community manager of an open source project, I find it naive to think that an open source project can thrive completely free of corporate sponsorship/benevolent dictatorship.
For example, I am hired by Treasure Data, Inc. to work full time on Fluentd (https://fluentd.org), the open source log collector. Treasure Data does use Fluentd, and Fluentd is a core piece of the technology that we offer to our customers. However, my boss explicitly tells me NOT to herd the community to serve our interest. Why? Because we know that we benefit a lot from the Fluentd community both for community contributions and awareness, and it servers our corporate interest to ensure that we stay on good terms with the community.
At the end of the day, open source community members are intelligent. They can smell when companies start exploiting the community to serve their own interest, especially in a way that's not beneficial to the community. So, in that sense, my response to the OP is "let the community decide. if enough people hate on community managers, they will disappear."
That being said, I can agree with the OP that "community manager" might not be the best nomenclature here. But that doesn't mean open source communities do not need the go-to person for ensuring the community's health and longevity. Whether that person is called a community manager, mailing list patrol, event coordinator, conflict resolver, or geek herder is somewhat irrelevant.