Creating a good text editor is hard. It's even harder if it's for programming. Also many people have their preferences (
https://en.wikipedia.org/wiki/Editor_war), so my guess is, that it was deemed a relatively minor inconvenience by the authors.
Another way to look at it is this: you're creating a 1980s-era computer. Might as well see how the programmers worked before the IDEs.
That said, I think contributions are welcome! :)