Funny, when you put it in terms of editors, the answer for both editors and languages leapt out at me: claims to hardcore-ness, personal preference, familiarity

Funny, when you put it in terms of editors, the answer for both editors and languages leapt out at me: claims to hardcore-ness, personal preference, familiarity, and basic human irrationality. We like to think programmers/hackers/whatever are all logical and rational because they code for computers, but... not really. All the usual social and behavioural weirdness applies.