Yes, they tested the iPhone in lab controlled conditions, which aren't exactly real life, like dropping your phone overboard, taking it for a swim in the pool or ocean, dropping it in a toilet. Under strict lab conditions, the phone stood up to the conditions it was designed to meet. That doesn't mean you can drop your phone in water, pour coffee or a soft drink on it, accidentally drop it in a toilet (which unfortunately happens to some people). And if the phone is damaged by liquid intrusion, which Apple doesn't guarantee against, then the user will have to either purchase an "out of warranty" replacement or a new iPhone as it is simply not covered under Apple's standard warranty.
So you need to do your best to avoid getting your iPhone wet. For if you do and it is damaged, it's going to cost you. And that's that. There really is no point in discussing this further. We aren't Apple. We are all users on this user to user only forum. We didn't engineer iPhone. We don't provide its warranty. Feel free to share your thoughts with Apple here --> Feedback - iPhone - Apple
You take care and I do hope your iPhone is safe and not damaged my liquid, now or in the future.