True.
Guess it's just not a priority for apple. Also even if they did do it they probably wouldn't advertise it, just because it would tempt complaints.
It's not just the Lightning port either. I've seen corrosion through the earpiece, I guess from sweat.
First my iPhone 6 is still fine, over a week later. I can tell you since I've seen it open, there are rubber seals on the home button, on off switch and volume rocker. There is no protection on the microphones, headphone jack, and lightning jack.
I've seen a couple videos where they dunk an iPhone. If it's under long enough for bubbles to come out, good luck. Mine was under for maybe 2 seconds, and I thought I did a good job getting the water out of the open ports. When they opened it at the shop there were a couple damp spots inside the case, about an inch up from the lightning port.