"McDonald's, Burger King et al" aren't really affected by this. This is about smoked, salted or otherwise preserved meats. "Processed" doesn't covered mincing/grinding. They may be covered by the weaker claims about red meat in general.
Burgers count towards processed meats. Especially when it comes ready made from a factory for the staff in the restaurant to heat up.
I don't think they would make that distinction and let it by. They wouldn't let any kind of meat be cast in bad light as it would affect them by association.