And? That account says:

1. Denim is not an American invention.
2. Jeans (the fabric) is not an American invention.
3. Denim garment, apparently including trousers (pants), is not an American invention.
4. Riveted pockets are an American invention.
5. The popularity of denim garment is originally an American phenomenon.

Of these, only item #5 is of relevance for JB's statement. But it only justifies using the word "invention" in its archaic sense, not in the sense "creation".