Special Edition defenders assemble!

“I have no doubt this boy is the offspring of Anakin Skywalker.”
“How is that possible?”
“Search your feelings Lord Vader, you will know it to be true.”

Yes, many Star Wars fans hate this line, but I cannot for the life of me wrap my head over these two things:

What is the justification for such a bizarrely specific dialogue alteration? As we know the 2004 SE’s changes largely served the purpose of bridging continuity between the PT and the OT, (an endeavour done poorly and quite in bad taste in my and clearly countless others’ opinion) since the emperor has been altered to his ROTS appearance, you would think that a dialogue change between him and Darth Vader would reflect that film’s events, but does it?
Palpatine tells Vader at the end of ROTS that he killed Padme, implying that her unborn child would have been killed as well, so if Luke’s birth was a truth that Palpatine had been concealing, why would he respond to Vader’s confusion about Luke’s existence by basically saying, “Well duh, how could you not have known?”
Was Vader discovering the birth of his children part of his ridiculously convoluted plan that the prequels established?
Before you say anything about Palpatine not actually knowing the twins were born at the end of ROTS, I know, I’m basing this argument on the assumption that in the SE, he learnt of Luke’s existence sometime before ESB.
Which leads me to address another blinding issue with this dialogue change, why does Vader act like a a clueless idiot and why would they make his line create a direct plot-hole with the opening of the film?
The opening crawl establishes that Vader is obsessed with finding young Skywalker, and in Vader’s first scene he refers to Luke BY NAME: “and I’m sure Skywalker is with them” so unless by the time ESB is set Darth Vader has forgotten that his name used to be Skywalker, him saying “how is that possible?” to Palpatine is one of the most bafflingly stupid changes you could make to the Vader/Luke storyline in ESB.
(And don’t give me that shit that he was just playing dumb to hide his defiance of his master or whatever, because not only is that tonally confusing to Vader’s ESB character, but it is NOT evident that this is the case in the SE version of the film.
What could possibly be the in-universe explanation for this confusing mess in the context of the ‘definitive SE canon’ or whatever Lucasfilm considers it? (I’m planning a topic on such an issue in the coming days buy the way)
Looking back at the questions I raised in my first paragraph, how is all of this contradicting, vague retconning and flimsy loopholes explained in post film saga material and/or in-universe? (Not that it really would matter to anybody on this forum, but it’s probably worth discussing)

Bonus points if you’re a SE defender and have some convoluted argument IN FAVOUR of this SE change! 😦