Disclaimer: I am not trolling, I am an autistic person who doesn’t understand so many social nuances. Also I am from New Hampshire (97% white), so I just don’t have any close African-American friends that I am willing to risk asking such a loaded question.
Interestingly, if you look at the menu for Juneteenth, it doesn’t include fried chicken. The only chicken is a dry rub chicken that wouldn’t be fried. So your evidence confirms they believe fried chicken is in fact not appropriate for Junteenth. That’s a good reference point if we all accept that the national museum of African American history is an authority on such matters.