Because programmers made the LLMs, and they first applied it to the problems they know, so the examples of "replacing a programmer" are abundant. Then the hype train rolled in and now it's suddenly going to replace everything, just that software engineering is the low-hanging fruit since they already have "proof" that it works in that domain.
Hint: it actually doesn't work at real depth, and why not is fairly well explained in TFA: they hype always overestimates the depth of the field. So these advances do help to make easy thing easy (in the case of LLMs because they have been trained on a billion examples of the easy stuff), but don't really end up helping with the hard things (because they really only make new things that weren't encompassed in their training by getting lucky, and because tedious things are different than hard things).
Hint: it actually doesn't work at real depth, and why not is fairly well explained in TFA: they hype always overestimates the depth of the field. So these advances do help to make easy thing easy (in the case of LLMs because they have been trained on a billion examples of the easy stuff), but don't really end up helping with the hard things (because they really only make new things that weren't encompassed in their training by getting lucky, and because tedious things are different than hard things).