Captain, first welcome to the forum.
Secondly you are assuming that another person would react to a gun grab by assisting. It has been shown on this forum that many would not, they carry to protect themselves and not a third party this even includes intervening in actual active shooter situations like those at Cracker Barrel and other places. I am not saying anything bad about them it is there choice plain and simple.
Another aspect to consider is that while yes it would be nice to know you would have help in a situation like that what kind of help are you going to get? Will the other person panic and draw there weapon? Will they come rushing in so assist only to lose yet another weapon because they are not prepared to physically defend themselves?
In a perfect world it would be great to think that folks would come to the aid of others in the face of adversity but unfortunately it probably won't happen.
I do agree totally with part of your post in that you must exercise these rights responsibly by showing a quiet professionalism when OC'ing and having an increased level of situational awareness at all times.