It’s long, but it’s not complicated. Stay with me.
1a : to go back or come back again
b : to go back in thought, practice, or condition : revert
2 : to pass back to an earlier possessor
1 : to bring back (something, such as a writ or verdict) to an office or tribunal
2 : to bring, send, or put back to a former or proper place
3 : to send back
4 : to give back to the owner
5 : to hit back (a ball or shuttlecock)
Maybe you noted the pattern. Apart from usages like “to bring in profit” or “to elect a candidate”, “return” always includes the concept of “back.”
“Return(ing) back” is, therefore, a redundancy. Nay, let us not fear to call it what it is: an abomination, and one that I have seen and heard too frequently of late.
There is a tide in the affairs of men.
Which, taken at the flood, leads on to silliness . . .
– Julius Caesar, Act 4, scene 3 (edited)
I hope that it is not already too late to stem this tide in the affairs of men: that we have not yet passed the point of no return-back. I hope, too, that we need never return back to the scene of this linguistic crime. I hope that if we collectively return back to our senses, we can return back as well to our former practices of speech and writing. I hope that we can return back any documents issued in egregious error (by return-back mail ideally), for prompt repair by those responsible for them. And in return-back? Our thanks. We would be correct, not ungracious.
In short, I hope that we can return back to the fold and, without being stymied by the law of diminishing return-backs, return back this practice to whomever its sender may be and in such a way that it does not return back to haunt us.