Context matters, yes. But context cannot change the literal meaning of words. At this point in time in the English language, the meaning of the word cocksucker is very clearly defined. It means "someone who sucks cock". Now, that in and of itself isn't bad because the word doesn't include any inherent value judgement. You could, in theory, use the word cocksucker in a completely neutral or even positive sense. For example: "I'm a great cocksucker." No issues there. However, it's usually used as an insult and when you use it as an insult you automatically imply that there's something inherently negative about the act of sucking cock or a person who sucks cock. And that is not changed by context. Even if you use it as an insult for someone who's never actually sucked a cock, even if you don't mean it literally, you're still reinforcing that negative connotation. That's a problem.
With insults like dick, jerk, cunt, bitch, I don't think that that's necessarily the case (though again, I don't know if there are any specific historical factors regarding the word cunt in the US). Like, referring to a person as a dick doesn't have much intrinsic meaning to it. They're obviously not a literal dick and, as far as I'm aware, there are no established discrimnatory stereotypes you're furthering by using the word dick as an insult...
And just for the record, I don't dislike swear words whatsoever. I use them quite liberally myself. I merely try to be aware of their actual meaning and if there are ones whose implications I don't like, I'll try not to use it. Likewise, I never use expressions like "that took balls" or "they didn't have the balls" because I find it to be inherently sexist (because it implies that courage is an inherently masculine trait which isn't only unfair towards women but also creates unhealthy expectations for boys and men to behave a certain way).
