I think the reason Squidward hates SpongeBob and Patrick so much is that he is clearly class conscious while the latter two are classic lumpenproletariat. SpongeBob has a love that borders on fetish for wage slavery, and Patrick's participation in the 1999 nematode genocide (head canon) (think about it the next time we see nematodes after the pilot it is very clearly a different ethnic group) because he was part of a Neptunian Brigade recruitment campaign targeting the unemployed.
Squidward, on the other hand, thinks himself a principled Marxist. He works because he needs to but is also incredibly willing to organize. In his free time he interacts with his hobbies, and his art is often critical of capitalism (second head canon). However he does nothing to start the revolution (besides something we will get into later), perhaps a criticism by Hillenburg towards the so-called Marxists of the western world.
Of course, in the episode where Squidward moves to the squid ethnostate we begin to create a narrative that Squidward's ideology most closely aligns with Zionist socialism, so it could also be possible that he believes the duo inferior for racial reasons, however that would only be the case before that episode because he clearly rejects the ethnostate by the end.
Perhaps we cannot blame Squidward. Two of the most popular people within the city state are Larry the Lobster, who is clearly a fascist, and Kevin the Cucumber, a kind of proto-groyper. It is also apparent beyond this that the society is fascist in the larger context, the representation of law and order are two old men who only maintain their status due to a romanticism of the aesthetic purity they once had.
This is of course why Squidward often doesn't mind interacting with Mr. Krabs. Sure, Krabs is a capitalist, but much like Stalin and Roosevelt united to stop Hitler, Squidward must be cognizant of the relative lack of threat Krabs' vision of anarcho-capitalist utopia (third head canon) represents. The fascists who run bikini bottom are clearly efficient, and any society Krabs could build in its place could not last as long, thus this would give Squidward a better chance to organize the masses if he so chose
"But offices!" I hear you, dear reader shouting at your phone "of course you genius of all matters should know that bikini bottom is a monarchy". Alas, we never see King Neptune govern, and we also see two completely different King Neptunes, which the residents of bikini bottom never address. This of course means that "King Neptune" is a ceremonial title, perhaps an overhang of the system the fascists replaced. Indeed, the best real life example would be Wilhelm II's hope that Hitler would restore his family to the throne.
Of course, in the end, no one will read this far into this post, so I will say that sometimes I take a condom from my nightstand and proceed to pee in it and tie the end. I then hold this piss filled condom in my hand and pretend it is the warm hand of a lover. This of course means that when I awaken, I am holding a vessel filled with cold foul smelling liquid, which allows me to remind myself that I am unlovable
