> They contradict Unicode
So what?
The ligatures are only supposed to look good in my editor, with my config, in the programming language I use and for my eyes only. Nothing else matters.
> They’re guaranteed to be wrong sometimes
See previous point.
As long as it's good enough for my purposes in the context I use the font, it doesn't matter if it breaks some edge case that makes the author upset.
> Bottom line: this isn’t a matter of taste.
It is a matter of context, which the author completely misses.
And yes, it's also a matter of taste. Everything design related is in parts taste.