While this note from the tech may seem comical - it may or may not be factual.
I'm trying to find an FCA SOR (Statement of requirements) or System design specification in my corporate database to see what FCA's standards are for sealing. Can't find anything at the moment... but their DFMEA's (Design Failure Mode Effects Analysis) say essentially the same as mine do - the weatherstrip must seal out water, dust and air at a nominal seal gap +/- 2.5mm of door variation.
I personally work mainly with Ford - and Ford states that you have to pass a 20 minute soak in a Ford Approved water booth. We have a water booth that has all the appropriate nozzles for each OEM and can run water soak tests for a full vehicle to verify we meet specifications.
All that being said - and assuming they have a similar requirement for the Ford spec.. A 20 minute soak isn't that hard to pass as long as your seals are making good contact. Imagine your spray attachment on your garden hose. Set it to the wide spray pattern and about 20 psi... Now imagine one of those nozzles placed every 6 inches front to back and about a foot apart all the way around the vehicle - no closer than 2-3 feet from the vehicle.
I found a pic online of what the water booth's look like:
You fail if you get a drip inside the cabin. Floorboards or door trim getting wet would also be a failure.
I can't tell you how many hours I have spent inside vehicles during water tests with a flashlight looking for drips...
Now - Commercial power washer spray is a "whole notha level!" Thats multiple hundreds of PSI - and no sealing engineer in their right mind would sign up to pass a point blank spray test of that magnitude... If you point a powerwasher right at your margin gap from a few inches away - NO seal will keep that much pressure out.
We do have to pass a "commercial car wash" - but that is no worse than the 20 minute soak...
I do disagree with the "Hard Rain" statement - that would never pass in the industry... Unless FCA has a "watered down" specification for the wrangler and it allows some leakage as long as the passenger doesn't get wet (i.e. floorboards and trim wet is fine).