IMO, each fisherman has to decide for him or herself what is, and what is not, sporting to use in bass fishing. Someday, modern technology will likely invent some lure or tool that catches bass and other fish every time its used where fish live. Some just want to catch fish and will use the best lure, bait or tool to do so. Others will want it to be a challenge. I thought that tournaments were supposed to be a challenge. Since the umbrella rig seems to take much of the challenge out of bass fishing, I agree with tournament directors banning it from their tournaments.
I, also, agree that since most bass fishermen practice catch and release, the use of an umbrella rig will not adversely affect bass populations. I am not against people using it, but I won't due to personal preference. Although in Missouri, it might be illegal to use with more than three hooks (treble hooks are one hook) at one time on one rod; not that anyone's odds of being caught are very high. OTOH, a court might consider one hook, like a rogue because it is only attached by one knot to the line; unlike a spider rig for crappie fishing.