It's an old shame for Itsuno
I think you hit the nail on the head there. You know, as a professional, it must not be easy to be associated with such a failure so I can see why he tries to ignore the hell out of DMC2.
Besides though, even IF DMC2 gets erased from canon... What does the series lose, really? It's not like that game introduces anything important story wise, another testament to its insignificance. Lucia is just another female side character that doesn't have the significance Trish had on Dante in DMC1 nor the depth of Lady in DMC3. Matier is... just there. Arius, idem, just another demon power hungry human that doesn't have the charisma and brilliance of Arkham or even the subtlety of Sanctus. Dante is a lost cause in that game as well, the most prominent thing about him is that coin trick.
The only thing remotely important is the Vie de Marli clan at the time of Sparda but the story of Sparda rebelling against its kind was an already known one.
Like, each game in the series, whatever its quality may be, adds something significant to the story. DMC1 is the start of it all, DMC3 gives Dante a bit more depth and makes Vergil an actual character that becomes as popular as his brother, DMC4 brings Nero to the roster of main characters. DMC2... what's it got?
I mean sure, its gameplay, however bad it was, still put down the basis for DMC3, so it's got its merits there, but I'm talking about canon wise, story wise. It is considered by so many fans to be such a detached title from the rest of the series for a reason. We're talking about references, or lack thereof, well
that's a game that does no effort at all to link itself to the previous title. It just wasn't a significant addition to the story, in any way. So, like, if it does get retconned out of canon, or if it doesn't get mentioned ever again in future games, I'm not gonna cry about it, honestly.
Now I know, I'm gonna get flooded by replies from people that love that game but this is just my point of view, you're free to disagree but at least try to think about my points is all I ask.