Then your previous statement makes no sense in context. At least to me.
Yes busybox knows it's busybox. But busybox doesn't do anything if it is not invoked in a certain way which relies on argv[0] being what it is today. I am not sure what you're arguing for frankly.
The article's lead argument for the "badness" of argv[0] seems to be, roughly paraphrased, that "the program should already know what it is [true], and this could confuse it [Huh? No I don't really know what that means either]". That's followed by a bunch of other stuff about other programs guessing what executable is running in a given process based on its argv[0], which is of course just deeply ignorant misuse of the value.
I mean, "the name" of the file that got loaded isn't even necessarily either well defined, or useful under any definition.
The hangup here seems to be the definition of "program". I'm using it to mean something roughly like "executable", which I think is fairly close to what the original article meant it to mean. You seem to be using some concept of "program" that makes each of busybox's functions a separate program. As far as I'm concerned, on the other hand, busybox is one big program that does a lot of largely unrelated things, choosing which of them to do based on how it's invoked. There's no right answer. You could say that all of the software running on a whole computer is one giant program, and in fact sometimes I do find it convenient to think of it that way.
I don't know that your definition of "program" is wrong, but I do think it's alien to this context.