I am not a HAES person, but I follow several dieticians who fall in the fat liberation/HAES type realm and for some reason I looked way into this over the weekend.
Lindo Bacon (they/them) is an author who wrote a book about HAES that is often seen by outsiders as a seminal text. However, Lindo does not "own" HAES (it may be a trademark that a non-profit org owns). It's the 15 year anniversary of the printing of the book and Lindo wanted to issues a new edition and went to the org to let them know and get feedback.
The Org was not pleased, in part because they don't think it's appropriate for Lindo to continue to be seen as a key figure in this movement. Lindo is of average size and white. They are trying, as an org, to make more room for fat people, as well as BIPOC people in leadership/prominent positions.
Lindo ignored the org. Lindo reached out to a black woman (Mikey) to see if she would coauthor the new edition with them. During the conversation, it seemed really apparent that Lindo would not really be willing to make any changes to the text (including things that Mikey disagreed with). Lindo seemed to be more interested in stamping the new edition with the name of a non-white person than actually taking Mikey's feedback or doing any reflection on feedback that they have received.
It seems like everyone's pretty exasperated with Lindo. There is an impatience with her work being seen as key to the movement, but with Lindo being "average sized." There has been a reckoning in the past few years about being more inclusive of BIPOC people. Lindo positioning herself with a new edition of a book that was seen as problematic by many has exasperated many people.
I probably got some things wrong here (and if anyone catches it, please let me know!). I was really confused about what was going on and read WAY too much about it. The people involved are very interested in providing every receipt on the topic!
In addition to what bears said, many people think Lindo Bacon created HAES, but this is not the case. The entire HAES movement began as a fat liberation, anti-racist movement. So it is really problematic that so many thin, white individuals continue to be seen as the face of HAES.