It really irks me that they are using the word "unbreakable". Unless it is truly unbreakable, you shouldn't get to use that word!
I'm not really disagreeing with you, but from a Sales/Marketing, and general understanding of products viewpoint, this is not unusual.
The terms Unbreakable, Unstoppable, Waterproof, Everlasting, have and are used all over the place, and none of them actually mean that if you take it to the extreme.
A block of steel or a rock is not unbreakable or everlasting, but most people would generally regard it as so.
These terms are generally used with a product is a LOT more that what would be expected from what ever product it's up against.
You guy a sheet of glass for a window, and it will break
You may see an advert for unbreakable window replacement made from polycarbonate, are they technically unbreakable no, but in comparison to glass they are so much stronger, that for general thinking, when set against the normal product (a glass window) the polycarbonate one, is unbreakable, unless you set out to break it deliberately.
If a phone with a glass screen breaks when dropped on it's corner from 1 or 2 feet in the air, and you then make a phone with an, as advertised "unbreakable screen" that survives this, in fact survives, perhaps 4ft, 6ft, 10ft type drops and does not break.
Then, for most people, whilst not scientifically accurate a term, it is AS GOOD AS unbreakable.
The fact you CAN break it using tools or extreme measures is not really the point.