No, because the sort of person who will force themselves to see Corrin as "a man" is not the sort of person who would give a gay couple homophobic abuse. If you can't cope with gay, you definitely are not on board with trans.
Now, this is where many FWR regulars will want to jump in and explain that gender ideology is homophobic in practice, which is also true.
At first glance my two statements would appear to contradict each other so I'm going to unpack this.
There many different voices and perspectives making their opinions known around trans activism and LGB rights, and ascribing motiviations to others gets very messy very quickly - person A may wrongly accuse person B of the same thoughts as person C because B&C C both disagree with A.
Corrin may well have had homophobic abuse from people with traditional ideas about gender and sexuality, but this abuse would be centered on her gender non-conformity (not being "butch" but rejecting traditionally female presentation) so would take the path of "she's cut her hair, wears a suit and she's not smiling and giggling for men, she must be lesbian". Nothing to do with Corrin's relationship being "a man" with a man, because while those people would indeed also abuse gay men, they would not see Corrin as a man in the first place and therefore not perceive the relationship as gay.
Surprisingly, despite the LGBTIAQ+ rhetoric some TRAs and trans commentators have said very homophobic things about (to use their concept) "cis" gay people. The key thing here is that the venom is directed at specifcally cis gay people because they are seen as gatekeeping or as pulling the ladder up. These people might (try to) see Corrin as "a man" but would not target her with homophobic abuse because she's the type of "gay man" they like. This abuse is homophobic because they are weaponising the language that most insults the group they are angry with rather than because they are motivated by conscious homophobia, if you see what I mean. (Unconscious yes, undoubtably).
And beyond both of this, there's the homophobia/misogyny underpinning the whole concept of trans identities, the unspoken assumption that if you are not "man enough" (or woman enough), you are actually a women (or a man). This intersects with the traditional first group in the assumption that gay men are "feminine" / feminine men are gay, and gay women are "masculine" / masculine women are gay. But this is never said out loud by TRSOH, and again would not surface as homophobia towwards a trans gay "man" because the gay trans man persona is fitting into this world view not challenging it.
(Apologies @franceslucia if your post was satire and I just springboarded an essay off it! But it's a good essay regardless).