The series 1 watch had the same caveats but proved very water resistant in practice. To make stronger promises you need to understand how the seals age and how the device behaves in lots of situations, or you need to over-engineer it with bulky seals and other compromises. You also need to understand and deal with extremely tight manufacturing tolerances.
If Apple said the iPhone was waterproof people would take it scuba diving then post YouTube videos showing how "crapp" the new iPhone is, then we'd have watergate (lol) all over the tech press.
Much like Trump/Hillary, people don't hold anyone else to the same high standard they hold Apple to. (If Trump manages to not vomit on himself at the first debate he'll be declared the winner by the media. )
