They are branded Disney, because the Disney brand is all over the credits.
Yeah, but most people walk out on the credits. Anyone who does pay attention to credits and creators would already know that, say, Touchstone or Miramax films are from Disney. It's not like it's literally kept secret; it's just downplayed on films that don't fit audience expectations of what a "Disney movie" is. That's the purpose of branding -- not to lie about ownership, but simply to set expectations about what kind of thing you're getting. For instance, the Nestlé logo is on the back of a Lean Cuisine package, but the fact that the big logo on the front says Lean Cuisine instead of Nestlé tells you that you can expect it to be a low-fat, theoretically healthy meal instead of candy.
Disney doesn't credit itself as Disney on R films.
But it does still make them, so I don't know what you're arguing. Haven't they already confirmed that they will keep Deadpool R-rated?