I'm baffled by how many ppl consider it plausible that the guy who critically failed the 'don't get attached' assignment would then turn around & be the most trite generic absent father stereotype to the one kid he could actually expect to live
imho ppl are deeply, utterly boring for jumping to that conclusion.
Like... this is the guy who couldn't stop himself from loving he believed at the time to be a walking corpse imbued with a substance he'd be instinctively repulsed from & that would inevitably go in the shredder, so much his regrets over how that went basically did him in.
Obviously his lack of a more direct appearance means something, but we're actually presented with pretty straightforward explanations for why Hornet would be 'mentally avoiding the subject' that are right in your face & don't require the extraneous insertion of trite old cliches, like:
She was basically pressured by the other Weavers to disown anything to do with him (this is the tone-setting sequence the flashback opens on)
She thinks she fucked up just like him (this seems to be the conclusion implied by the journal entry effectively replaces any direct appearance by him, & just the way the preceding bits were building up to, where she reflect on what she learned from each of them. It's like a missed/subverted rhyme. )
Especially since the fiasco is the result of going against precisely what the scheming aunties in the flashback would've wanted for her (likely something in line with the default ending)
Like come ooon it was such an interesting subversion that the aloof, stoic engineer guy was the one to get attached and not the sensual, more sociable nature lady. (who thinks he must've fucked it up by going soft) Why'd you go & flatten that whole intriguing complexity to replace it with a boring 50s sitcom standard marriage??
From a doylist perspective, they're obviously keeping the aesthetic/mystery consistent with the 1st game; (he's really no less present than the ladies, but it's done through his constructs, BGM, statues, architecture...) - they very deliberately avoided having him around to explain himself in the 1st game, & they're not gonna ruin it all now. That, & 'rule of three' / wanting to give WL some spotlight as the one who arguably needed it more/ didn't already have an entire area dedicated to developing/exploring how she feels about stuff - she's effectively speaking for both of them, but having her show up (& talk to someone who isn't Ghost) gives us much more new info about her than a copypasted version of the pop flashback with baby Hornet would've told us new things about him.
plus this flat "insert tired stereotype here" thing ignores pretty much all other clues/ hints we get at what's happening there.
Like bits indicating that she very much did have positive memories of the white palace, like comparing a flower creature to its decor after calling it beautiful, or the whole 'fondness for radial blades' exchange - so much for the fanon that she hates the place. Having some respect for knightly types like Garmond & Second Sentinel despite having left behind her earlier idealism... or how she consistently refers to Hallownest or its cavern system as her home not just Deepnest alone & the tool pouch she carries around has Hallownest's emblem on it. (thus each of her starter equipment bits represent some aspect of her origins - the needle is from the Hive & the red cloak is from Deepnest)
Then there's the whole 'princess knight' thing... - would she have chosen to work at the court if she totally loathed everything he stood for? I doubt she couldn't find a job in Deepnest.
Don't get me wrong, clearly she had no illusions about the guy, given the main thing that comes to mind for her is 'ah, these were his initial clumsy prototypes!' (but she knows exactly how they work, probably cause he explained it & that's why she's now probably surpassed him as an engineer)
But you're not just restricted to the binary options of blind admiration & complete repudiation, indeed it's the mark of a mature mind to be able to have a more differentiated view.
There's such a thing as ambivalence/ mixed feelings, which is probably the case here - not just with regards to him, but it also applies to everyone else, like she tells Shakra she doesn't know what Vespa would think of her & there's the whole ending Huntress questline, & she obviously disagreed somewhat with with WL regarding what to do about the Knight.
But at the end of it she very explicitly says that she doesn't hate or condemn any of them & actually kinda gets them - that's very compatible actually with having ambiguous feelings or points of disagreement.