It has nothing to do with the Arduino, it is a general ee question. Is this another baseless "because they have an sucky Arduino" migration?
Arduino mod here. I've been asked to migrate the question back to EE, but in this case I'm inclined to leave it on the Arduino site.
I think it's a decent question and is potentially within the scope of either site. The main reason I'm not migrating it back is because it's been answered. The goal of migration (according to the Stack Exchange guidelines) is to ensure a question has the best chance of a good answer. It seems to have got that now so re-migration seems unnecessary.
However, I agree with those who are saying it shouldn't have been migrated to us in the first place (or at least not quite so quickly). The question was about the shift register, not the Arduino itself. If it had been lingering for several days with no answer then it might be different. Please try not to jump-the-gun though.
It was migrated in the context of Operation: Migrate Everything.
It should not have been migrated, since, as you've said,
OP in that question is purely bit banging a shift register without any real libraries being used aside from some basic macros that every microcontroller uses.
Unfortunately, there does not seem to be a way to stop all this migrating. (Y)our best bet is to flag the post on Arduino.SE, and ask for a migration back. I've done that successfully before.