Slightly OT, but down sleeping bags carry the same caveat on detergents. There are specialised, non-sudsing liquids available at outdoor shops (at least in Australia) that are specifically made for down bags. I imagine it has something to do with ensuring the loft on the down remains "lofted" (if you know what I mean), rather than compact through use of laundry detergents.
I did note the washing instructions on my Australian down bag said to use soap rather than detergent, and I did so on a recent trip to Iowa with no ill effects.
On-topic, GoreTex apparently doesn't mind a bit of heat treatment. I have watched a hand from a maxi-yacht in the Sydney-Hobart ocean race put four loads or five of GoreTex sailing jackets and trousers through the washers and then quite warm driers.
I have read that going over the fabric with a warmish steam iron will restore water repellency. Go to this link and select Re: reteflonizing gore.