It's subjective because you haven't defined or quantified elegance or understandability. I could say that zero based indexing is not in fact understandable based on the amount of confusion I encounter explaining the concept to new users. I could say it's inelegant based on the fact it makes algorithms I use harder to implement. Others argue it's more elegant because it makes algorithms they use easier to implement. Same rationale, subjective conclusions.

Dijkstra's argument as well hinges on an undefined notion of "ugliness", which can mean anything to anyone. That's why these conversations never end, because most people are talking past one another based on their own definitions of "elegance" or "ugliness".