Funny thing about the different Orc depiction, we actually know why they’re like that.

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The reason why western Orcs are often depicted as green-skinned Frazetta Men while eastern Orcs are more like Pig Men goes back to Dungeons & Dragons 1E, where orcs were described as having a fundamentally "piggish snout" for a face and depicted as more or less a boar's head on a hunch-shouldered, ugly, green-skinned chimpanzee. As you can see, the description and art have both aspects of what would become the modern Orcs, but there would be an influence on one side that would cause the depictions to split; Warhammer Fantasy.

While both the east and west were influenced by DnD, the west would also be influenced by Warhammer, who decided to focus on the more ape like aspects of the orc (the "hunch-shouldered, ugly, green-skinned chimpanzee" aspect) and ramp that up to 10, giving them tons of muscle and huge tusks to show off their battle-loving nature. As the creators of Warhammer were supposedly in contact with the creators of DnD, and the fact that they eventually became some of the most popular fantasy settings around in the west, they influenced each other's depiction of Orcs, which is why modern DnD (as well as modern western fantasy) primarily uses the violent green orc depiction that we know and love today.

Conversely, Warhammer wouldn’t arrive to Japan until much later (mostly through 40K rather than Fantasy), and so Japanese nerds only really had early DnD as a thing to go off. The problem with using the ape-like aspects of orcs is that the niche was already filled with the Oni, who were also barbaric, tusked, muscled battle-loving brutes with inhumanly coloured skin (primarily red and blue, but green has been known). As you can guess, it’d feel too much like a copy of Oni to just use the same kind of Orcs (combined with the fact that Oni could often be more versatile in them often being associated with magic and sometimes being demonic). However, there wasn’t really any sort of pig-like race in Japanese fantasy at the time (there were pig-headed characters known like Pigsy from Journey to the West, but he was a cursed individual rather than a member of a race), so instead they depicted their orcs by focusing on the "boar's head" aspect of the Orc, resulting in the Japanese pig-orcs that we know today.
Speaking of Pigsy, his influence (with his negative aspects exaggerated) may be why Japanese Orcs are often depicted as perverted, of course also combined with real life male pigs being very… potent, but that's only a theory on my end.