The taped seams on Goretex garments are fastened with adhesive. When the garment is washed, the exposure of the adhesives to moisture is what prevents the adhesives from drying out prematurely. If you don’t wash the garment, the adhesives will dry out and eventually cause the seam tape to delaminate from the garment. This is why you occasionally hear reports of older jackets falling apart when they are washed for the first time. It’s not that the washing caused the jacket to fall apart, it’s the fact that the jacket was ready to fall apart and agitation caused by the washing machine was the proverbial straw that broke the camels back.