Didn't you see the shit that Dante was surviving though? The shit with the sword going straight through half his body which he pulled himself off of through the f*cking hilt, that probably at least grazed his heart, Dante isn't too wide.
And they weren't talking about Dante's feats against normal demons when referencing Madama Butterfly, they were talking solely about his whole "Blocking a punch from a Godzilla-sized supernaturally enhanced Demon statue thing".
The Saviour has to be way up there in terms of strength, and you have to think about all the stuff that Dante has shrugged off.
Also, running towards the ground at Terminal Velocity is pretty insane. The only time we've ever seen Dante really struggle was against the Verse' strongest. People like Mundus and Vergil, besides that, everything else is a cakewalk.
Dude's been borderline cut in half, impaled by stuff for several minutes without much trouble. Its just some stuff is inconsistent, like his fight against Vergil put him down when he wasn't even beat that badly, he was just stabbed. Whoop-de-freakin doo, I think it was more of Vergil's sword being super crazy insanely powerful and OP, and less of just Dante getting stabbed.
Even Nero beating the ****ing SHIT out of him, stabbing him through the chest, shooting him, and slashing him a few times didn't even make him break a sweat.