John,
The two main factors that define the amount of trash and overall damage in the wilderness are traffic and the attitude of visitors. If you climb elsewhere in the High Sierra, you may realize that Mt. Whitney actually falls in between Yosemite and other, more remote, peaks because the folks visiting those peaks are fewer and generally more responsible than average tourists. When I first hiked the entire JMT, I was impressed how relatively clean the trail was (except for the Valley part, which I also try to avoid), despite all the traffic. Again, the reason is simple: there are not many tourists. Considering that NPS is unable to enforce the LNT rules effectively due to limited staff and the need to focus on immediate problems (fires, rescues, restoring trails after winter damage) and that the extent of traffic in the Whitney zone is unlikely to change in the near future, the two complimentary solutions are better education and community efforts to clean up. I personally view the latter as a small payback to the nature, not a heroic effort to brag about. Again, I hope you understand that I am not tying to advocate the offender in this particular case of suggest that removing the tag is not necessary. I simply feel that the issue is being overdramatized and that it needs to handled by professionals. I also firmly believe that plastic scattered in the area is a much bigger problem.
Best
Anton