"Him" because "people" is the direct object and "him" is merely a stand-in for the direct object.

All of these would have the meaning of 1d. b and d sound very strange and may be incorrect. If you really want to be understood just say: I dislike people like him.

All four sentences you provided have different nuances, and only some of them are grammatically standard. Here’s a breakdown of each: 1a. "I dislike people such as him." Meaning: This sentence suggests you dislike people like him, meaning people who share similar qualities to "him." Grammaticality: This is grammatically standard in informal English, as using "him" here is common in casual usage. Interpretation Accuracy: Yes, it’s close to what you guessed, as it indicates that "him" is an example of the type of person you dislike. 1b. "I dislike people such as he." Meaning: This structure is less common and sounds formal or even outdated to many native speakers, as "such as he" sounds stilted. Grammaticality: Grammatically, it’s correct if you use "he" as the subject, suggesting "people such as he (is)" in a formal sense. Interpretation Accuracy: This wouldn’t mean "he dislikes people too." Rather, it’s another way to say you dislike people like him, but it sounds less natural. 1c. "I dislike such people as him." Meaning: This phrasing suggests that you dislike people of his type or kind, where "him" is specifically included as a reference point. Grammaticality: This is grammatically acceptable in casual English. It implies "people who are like him," directly pointing to people with his characteristics. Interpretation Accuracy: Yes, this aligns well with your interpretation, meaning you dislike "people, including him." 1d. "I dislike such people as he." Meaning: This is similar to 1c but more formal. It's less commonly used in everyday speech. Grammaticality: Grammatically correct in formal English, though it may sound stilted to some. Interpretation Accuracy: It’s close to what you said, meaning you dislike people who are similar to him, though "such people as he" may sound slightly awkward in modern English. In summary, 1a and 1c are the most natural and widely accepted forms in casual English. 1a is commonly used in spoken English, while 1c is a bit more specifi

They're all grammatically valid and have the same meaning. The meaning is mostly like this: "I dislike people who are similar to him." Plus there is a bit of meaning like this: "I dislike some people. For example: him." Note that 1A & 1C are normal speech; while 1B & 1D constitute a rare posh/poetic/archaic way to speak, so much that some people will think they're simply wrong grammar.