I totally agree and have read supporting evidence backing your entire first paragraph. But I've never seen that evidence suggest chicken and watermelon fell into the chitterlings and ham hock category.
Yeah that's why I say I think it's just a misunderstood thing coming from that tract; meaning over time casual associations of certain food groups now considered "staples" of soul food became less and less understood and discussed along with other aspects of that era of time to the point where foods that were never there to begin with got tossed in, no one checked it and everyone else ran with it.
Take Huey P. Newton for example, I've had plenty of frank, honest and open discussions with individuals who want to tell me everything they know about Huey P. Newton and his "radical-ness" and his "anger" and his "passion" as a Black Panther because of whatever oral tradition they've had passed down to them informing their viewpoint of the man-but it never goes very far beyond surface-level descriptions, and rarer still his philosophies or doctoral essays. Substitute Newton with James Baldwin, Clarence Thomas, MLK, heck even Dr. Cornel West.
I think the same unfortunate blurring of the culinary traditions of Black Americana has happened re: Fried Chicken and Watermelon-thin, surface-level oral traditions passed down time and time again until we got where we are now "Fried chicken, watermelon and purple koolaid" are for good or ill tied into every conversation of "black foods".
Thanks for clarifying. I can see exactly what you're talking about when I hear people talk about how Malcolm X needed to die because he wanted to kill all whites as if he wasn't excommunicated for preaching peace and unity after his pilgrimage.