Curate, connect, and discover
Voldemort feared the halfblood boy more than the pureblood boy because only a halfblood straddles the line between inexcusable weakness and birthright power. Only a halfblood boy would have the hunger to rise up against him, especially since Voldemort had positioned himself to be aligned with the pureblood upperclass.
I don't think he intentionally thought of Harry as an equal over Neville. I don't recall whether or not he heard that portion of the prophecy from snape. But we do know that both the Potters and the Longbottoms 'defied' him thrice. I'd always understood the Longbottoms as older, old enough to be well established and known aurors. Perhaps they fought for years during this 11-year-long First Wizarding War, perhaps neville was a conscious choice that may have seemed like an act of defiance but certainly wasn't an act of defiance to Voldemort himself. The Longbottoms no doubt had ample opportunities to clash with Voldemort's plots and plans. The Potters on the other hand joined the Order as teenagers with nothing more than some vicious schoolyard scrapping to their resume. I'd always liked the theory that their choice to marry and keep the baby (that became Harry) in that political climate when they were only 20 years old was itself an act of defiance. But the other two instances during which the Potters 'defied' him must have resonated. Lily must have said something that stuck with him, that forced him to forever associate her with his weakness, with muggles, even though she was not a muggle but a mudblood. A talented witch that even he noticed enough to consider snape's plea to spare her but also unforgettably "muggle". And James must have made enough of an impact for Voldemort to memorize his countenance years to come -- voldemort doesn't usually remember all his murders unless they meant something personal to his journey to immortal power. Yet somehow Voldemort recognizes the need to turn Peter so thoroughly and somehow Voldemort remembers James standing tall and formidable enough to try to taunt Harry with it at the graveyard.
Both Lily and James Potter had been living rent-free in Voldemort’s mind for enough time that their halfblood child was the first kid to pop into his mind at the news of the prophecy.
Also, Voldemort believes in pureblood supremacy the way Jordan Peterson is a Christian who believes in Christianity as salvation...aka, its largely a cloak for the pursuit of power, gets him the connections with the right people, he's conviced enough people with his narrative that it almost seems like he's convinced himself, but there’ll always be signs.
I wasn’t sure how to incorporate this into the options, but add in the tags if you think he also hated purebloods!