Yes, it's meaningless. Your accent is the way your voice sounds when you speak.
That's what I mean by obtuse. I always enjoy our debates, but to step further into this one, it is clear that neutral means "normatively standard" in terms of comprehension, with respect to other dialects / geolects.
If you and I, and several other speakers, read a fairly lengthy passage from a well-known text, and we put them on Youtube with and without subtitles and asked people to rate the clarity of our pronunciation, diction, oration, and so on, we would not all receive the same results.
You claim (it seems) this obviously predictable spread in results would be entirely subjective, entirely random, or entirely noise. Some sort of meaningless. I claim it would be partly subjective, and partly based on actual measurable criteria.
My pronunciation of /eI/ as in day, for instance, might perhaps be considered "close" to 15 of 20 other dialects. Maybe your pronunciation might be considered "close" to 13 or 14 of the same 20 dialects. It's distance from /aI/ as in "die" might be considered "clearly distinct" by 900 of every 1000 viewers, in my case, whereas perhaps your pair might be considered "clearly distinct" by some other number.
This is not a set of contrived or artificial questions. We could easily enumerate 100 or so criteria which would reflect common phonemes in English.
So while I would agree that there is no accent that can be defined as "neutral" --- none at all --- this does not mean we cannot reach relative conclusions about which are more or less neutral.
No one in the class needs to be exactly the average height for an average height to be calculated. Nor do we need to deduce from this that there is no such thing as height, or averages.
I hope you see some sense it what I am saying.