Sounds more like a fact to me.
That's your opinion.
It is fine to have an opinion.
Doesn't make it factual because it sounds like a fact to you.
The fact is that non-linear distortion adds things that aren't there and have changed the waveform.
is there a clear and universal/standardized definition of (audio) distortion?!
There is no single definition of (audio distortion). There are several types of distortion. One is more detrimental to (perceived) sound quality than others. They are all measurable and verifiable and there are audibility thresholds depending on the applied stimulus.
When the goal is to
reproduce a waveform exactly no alterations are preferred. (Is what ASR is about)
In practical sense this means low distortion (linear and non-linear) or for most at least inaudible (thresholds) levels.
When the goal is to reproduce soundwaves at a certain listening position that as closely as possible resemble the original waveform then the
electrical waveform has to be altered in such a way that the final result is least changed. This may be done by changes in phase and amplitude but does not involve adding frequencies that aren't in the waveform. (Also is what ASR is about)
When the goal is to listen to
preferred sound and one has a preference to do it in this or that way... fine, great for you. All bets are off and is not what ASR is really about but some still prefer. Add whatever you like. Don't say it is 'better' for music reproduction. It is preferred/like by some.
Then there are audibility levels.
When you realize the implications from above it should be clear that there is no single definition in audio. The only reasonable definition is that the applied signal is as close as possible to the original (fidelity). There is an electrical path and an acoustical path here and the third factor (the least quantifiable one) is perception where also preference plays a role.
That last bit is where your poll is 'fuzzy' and not ASR alike. The first 2 are. This makes your poll utterly inconclusive and you should have worded it better and give better options. That is if you want to find out how ASR members 'think/feel/opine' about distortion levels and types.