Evidently, every participant of this thread agrees that preserving the wilderness is incredibly important and we all should play by the rules. I can also share stories about carrying non-trivial amounts of someone else's trash from the Whitney summit for 150+ miles, on speed hikes where every ounce makes a difference. To elaborate my reasons for having a slightly different opinion on the OP, I'd like to ask you a few questions.
Do you practice the LNT principles because you truly love the nature or because you do not want to get caught and punished? I certainly hope it is the former, but the begging of this thread is largely focused on punishment and labels. Check the definition of vandalism. Although the lady's actions were clearly not OK, does she deserve to be labeled as a vandal and permanently banned from national parks if her intentions were sincere and she simply did not know better? Perhaps you could also think how such a label could impact her career.
Do you know how to appropriately remove paint and glue from granite? I can tell you from personal experience from a massive organized cleanup of a climbing area - it is not an easy task which requires special equipment and tools. So unless you know what to do, leaving this task to the rangers may be a better option.
After all, Mt. Whitney has not been ruined, the tag will be gone soon one way or another, and the fumes will die down. I just wonder if the energy of this discussion could better channeled towards solving the problems that are more substantial and persistent. How about adding a resource to this website that will educate the new hikers and climbers and will encourage them to spread the knowledge, since the NPS guidelines are still not being heard by everyone? How about reaching out to park rangers with the idea of starting an initiative for regular cleanups of the Whitney zone by volunteers? There are many inspiring examples, and I would be thrilled to join.