I am trying to have an open mind regarding this matter.
I'm supportive of local and global bans in a variety of circumstances, and if WMF thinks that sanctions are appropriate then I generally would expect WMF to present the relevant evidence to community authorities. English Wikipedia has ways of dealing with editors who are accused of misconduct, and we have experienced administrators who are capable of investigating situations and implementing bans including cases which involve nonpublic evidence.
In the absence of convincing evidence that demonstrates a major problem with a Wikimedia community's competence and willingness to adjudicate cases in a fair manner, I think that WMF interventions such as this are difficult to justify. Based on the limited information that I have, I disagree with WMF's process for this specific case, and in general I have ongoing concerns about WMF's process for WMF-initiated bans. WMF's lack of faith in the English Wikipedia community authorities' competence to adjudicate a case such as this is discouraging and, as far as I know, not justified. Even if a local community has well known problems with its self-governance, I think that the appropriate recourse would be to the global community. While the global community seems generally opposed to reviewing appeals of specific local cases, I think that evidence of systemic problems would likely get more attention and perhaps even a request from the global community for WMF intervention.
Based on the information that I know, I would reverse this WMF action and move the case to the English Wikipedia Arbitration Committee for its consideration.