Inevitable been thinking about how that one anon viewed Laios as a monsterfucker, and I think it made me realize the source of that confusion:
I think many monsterfuckers, and also many (dare I say most) monster devourers like Laios, both derive their desire from the same source: a latent wish for apoteratosis, the wish to become a monster.
Linguistic side note: apotheosis, becoming a god, breaks down to apo- (towards the end point), theo (god), -osis (turn noun into verb), so I swapped in the root for monster, hence apo- terato -osis. Side note over.
Monster devourers are a rather rare archetype in (mainstream) fiction, but they do exist. Those who seek to mimic or emulate the monster's power, those who find them endlessly fascinating and study them well past the point of obsession, those who wish to show their dominance over the monster by proving that they can kill and eat it... and I think Laios is the first I've seen who takes the title quite so literally, where his obsession goes straight to monsters-as-food.
Monsterfuckers, meanwhile wish to become close to the monster in a non destructive way (or at least a typically less destructive one, usually the only casualties are furniture and few bandages are needed, but I'll acknowledge that exceptions definitely exist). They wish to bond with it, to connect to it through lust or intimacy, to be able to stand at its side. They wish, on some level, to join it. Side note, I'm not saying this is true of all teratophiles, some are just kinky and driven by the thought of positive physical pleasure, or who find the personality of a given monster appealing, but I do think the apoteratotic desire is an underlying driver for many, I'd guess well more than half, it's just a subtle enough thing that I don't think most are consciously aware of it.
There's also a third point to the secret apoteratosis triangle that might surprise you: the monster slayer. Sure many, even most, slayers are driven by something like disgust or xenophobia or even rationality, but a significant minority land in the "if you can't join 'em, beat 'em" a.k.a. "I can't be you, so I'll destroy you" camp.
And these three reactions are, I notice, the three most common reactions that people have to one thing: the unattainable desire. The sentence begins "I cannot have it..." and these three camps end it different ways.
The teratophages say "so I shall dominate it." They seek what power they can grasp so they can have some modicum of control, so they can try to "have" it anyway. The kaiju corpse scavengers in Pacific Rim including refined and suave mob boss types just smacks of this attitude.
The teratophiles say "so I'll get as close as I can." There's a werewolf romance book where they're considering trying to turn the girlfriend, though they have no idea if she'll survive it (boyfriend was turned by accident then abandoned, so he's clueless, and they haven't found any others to teach them), and she says that she's fine remaining human, because she shares the power through him. "I have it, because you have it." The façade eventually breaks and in a vulnerable moment she confesses that she'd be willing to risk even a likely death to try to be turned. When they get in contact with an elder who can turn her safely she doesn't even wait a week.
The teratophobes write that whole sentence as "if I can't have it, then no one can." I'm sure everyone has seen enough examples of this behavior to understand that it's just a kind of love turned corrupt.
I'm not the first to notice the underlying apoteratotic urge: the aforementioned werewolf story, indeed many werewolf and vampire stories romanticize the transformation of a human into a monster. Back to Dungeon Meshi, author Ryōko Kui is fully aware of it with how Laios's underlying desire is eventually brought out of the subtext and explicitly named as his dysphoria with humanity, and his wishing that he could be a monster. For Laios that desire skipped right past the socially unacceptable monsterfucking, explicitly a form of bestiality in that world, to the socially acceptable devouring, though tempered by his respect and admiration of monsters into a desire for symbiosis with them. He cannot become one in truth (or so he thought when younger) but he could become part of their food web. It's as close as he thought he could get. Of course, that's the Watsonian explanation; the Doylist explanation is that Ryōko Kui wanted to subvert expectations, and also wanted to explore this angle of it.
So, all taken together, I think people read Laios as monsterfucker coded simply because teratophiles, teratophages, and teratophobes all share the same root motivation: apoteratosis. Thus, all three branches are coded very similarly.
It's similar to something I've seen in Batman fandom: some fans project romantic love between various members of the Batfamily, which is both wildly against canon and thoroughly hated by some other branches of fandom. But it is understandable, since familial love and romantic love both come from the same root, love of another. If someone doesn't recognize the simultaneous similarities and distinctions, it's all to easy to conflate them. If you don't actually understand the distinction, then the signs of affection between siblings might look the same as the signs of affection between lovers. Likewise, if you don't understand the distinction, the urge of the monster devourers (or ecologists) might look the same as the urge of the monster fucker.
I've sat on this for near a month, partially because of my repeated absences, partially because I wanted to honor it with an equally in-depth response. But 24 days later I've still got nothing, while I can't speak for that particular person I think in general you hit the nail right on the head for the base roots. I got no notes. Even with Laios...like all I can add is how supplemental materials actually confirm he did want to be a monster researcher but found books too dry, the only one who seemed to really *get* monsters was shunned. and how wild he goes when talking with an actual werewolf, "The existence I thought unobtainable is now right in front of me".
