Yeah of all SaaS-and-OSS linked projects, Wordpress strikes me as incredibly innoffensive. This is like getting mad at Canonical for owning Ubuntu.com and selling addon services and support contracts.
(The fine print: 1. I don't know any more recent examples and 2. I don't want to get into an argument about the definitions of "forcing", "their addons", "users of", and "the open source project".)