Probing of Kevin versus Tortured Wrestling Match
You know. there's a lot of differences between how Big D handles an interrogation and how Marckus, Dorn, and Kitten handled theirs.
In Tortured Wrestling Match, other than the obvious mistake of letting the vampires fight to the death and eat each other, none of Big D's sons (and son in law) try and connect with the vampires. To be fair, the chances of successfully doing so with them in a group is low, but there is never any intent to do so on their part to begin with.
Compare with Big D, who immediately latches onto Kevin revealing that he owns a pet cat. Ad Big D would know the significance of that, after all.
Now, if Kevin didn't do that, then I'm not sure how their interactions would go. I doubt Big D would be nearly as empathetic if Kevin was less 'human'.
But also his weapon of interrogation is mostly a pan. And omelette. But mostly the pan - compare that with Door stabbing the vampires with a spear.
Also just the general ways they see the vampires and all. Door is contemptuous of them, while Marckus and Kitten are curious about them to varying degrees. With Marckus eager to torture them as well.
Big D seems more...nuanced in his views. He definitely has elements of Door's, Marckus's, and Kitten's views. But as we saw he is able to emathize with at least some vampires - those willing to engage with him at least. And even converse with.
Though, to be honest, the only vamp of the basement trio that I can see D reaching is Shitbeard. Maybe Apeboy? But whether they would have responded on the same level as Kevin I'm not sure.