Everything else is politics and philosophy. Some people really get into the very specific politics and the very specific philosophies of the FSF. What they don't seem to get is that the FSF merely has one out of infinitely many perspectives on why open source is important and what people should do about it.
It's fine if someone wants to run an ideologically pure (per FSF criteria) FOSS project, or not contribute to projects that don't meet their criteria for ideological purity. Where it gets counterproductive is asserting that one group's philosophy has some sort of primacy over the entirety of the FOSS world. It gets especially dicey when that group claims moral superiority over everyone else.
Instead of complaining about this or that FOSS project not being "true FOSS", the FSF should define a set of standards and practices that go beyond mere software licensing that DO meet their standards for ideological purity. Then a project that wants to comply with the FSF have an easy way to state up front that they are politically aligned with the FSF in every respect. Those who care about such things can use that information to set their expectations about how the project is run outside of the software licensing aspect. Maybe it draws them to the project, maybe it drives them away, but at least no one gets surprised and no mailing lists devolve into pointless political flamewars.
That way no one gets disappointed (for example) when a project wants to use Slack for communication, assuming that that project has not stated up front that FSF-compliant ideological purity is a goal. Alternatively, if a contributor to a self-declared FSF-compliant ideologically pure project wants to use Slack, the other contributors to that project have grounds for denying that on a purely philosophical basis. They can focus on maintaining their standards for ideological purity rather than continually arguing over whether or not FSF-compliant ideological purity itself is valid goal.