The main issue is that NTR cliches are SO intrinsically ingrained on the minds of most people that enjoy the genre that when you stumble upon a 'weird exception' like SAO actually is, nobody really sees it XD Like, ironically, none of the non-Asuna girls in SAO being fucked or 'stolen' by other guys really counts as NTR, not even because it's one-sided but because Kirito is happily in a relationship since practically the beginning and the other girls canonically accept and are happy for both him and Asuna despite their own feelings (And this one goes extra-hard in Suguha's case who actually confessed and was rejected by him onscreen), without any attempt at pushing or the typical fighting over most cliche harem tropes cause. Yet, you will find that over 90% of the content of other girls being fucked by others still ends up labeled as NTR in sites like Pixiv or the like or tried to be portrayed as such because for most people that enjoy the genre just seeing a girl who likes the MC being fucked by others "is NTR" even when it really isn't XP (Hell, this game had to heavily alter both events and how the characters act/view each other to make it as NTR-feeling as possible because Fujino most likely realized sticking to canon in any level post-Aincrad wouldn't really have felt "NTR enough", that's the entire reason the whole of the Fairy Dance/ALO arc essentially never happened and Suguha never got her canon character development...and she was still written massively OOC at the start of Part 1 anyway to enhance the 'not-NTR'-feeling further :3)
But I kinda get what that guy means, because at least the Liz x Inoda scenes are a sign of the plot moving forward in some way, Inoda x Asuna is basically what happens every day now whether there is actual progress or not XD
