If you look at my bio, you'll see that I have been an ostomy nurse since 2001 and I have been a permanently ileostomate for 12 years (medically retired). I have seen this topic come up time and time again, and sometimes people are quite passionate about it. Based on my experience, I have formed the following opinions:
1) Rinsing the pouch does not control odor.
2) Rinsing the pouch can loosen the wafer.
3) Most ostomates do not wish to look at their stoma or their 💩.
4) It is inconvenient to rinse your pouch with an active lifestyle outside of the home.
As for myself, I regard the end of my pouch as my prosthetic anus (as I do not have one anymore). Since I never washed that far up from my natural anus, I see no reason to start now just because I can see 5" (apx 12cm) past the anus. With regard to odor, I think ostomates have the advantage. If anybody else has to pass gas, they have very little control. We just have to slip off to the restroom, pop the cap, and leave all the dirty smells there.