Yep. SAO, the anime at least, is very clearly a young teenage power fantasy and a badly written one to boot. Kirito is not likeable, got abilities that are equivalent to hax, and gets girls that he quite frankly doesn't deserve. All of that makes Kirito NTR desirable to people. "SAO is trash" was a meme and popular opinion for years for a reason.Kirito's only saving grace is plot contrivance. He is not strong, he is not powerful. He is weeb gamer who lucked into every single situation. Even in gaming, debatably his singular skill, he is only successful to any degree because the plot demanded it. He is decent if you want a no-thoughts, head-empty self insert to project yourself over. I imagine most people who would do this are also weeb gamers. I do understand the appeal, but from a storytelling perspective, Kirito is an abomination. If someone like Kirito actually went up against any of the people he does in real life, and the plot didn't contrive his victory in absolutely implausible ways, he would have his twink ass kicked so fast and hard he would never recover. These traits make him an inherently unlikable individual, and thus, one that is gladly and eagerly sought out to be cucked by fan works.
Granted, I can only speak for his anime portrayal. I myself have only read the first LN, but with thatin mind at least, unless the quality of the writing improves greatly within the LN series, I would say he is pretty pathetic either way.
The LN may be better, but the meme of chapter 16.5 still shows that the author was not that great of a writer and turned many people away from ever trying to get deeper into it. That and the fact that the gratuitous rapey stuff is still in the LN, as far as I know.