It's not absurd. I think HorneTD is absolutely right. (He is, I believe,
an electrician incidentally.)
My recollection, from dim history, is that for soldered connections at
boxes the wires were cleaned and twisted and pointed down. Then the
soldered connection was made by dipping the connection in a solder pot,
with all the connections soldered in sequence at the same time.

Bud (also an electrician)


Doug Miller wrote:
solder but it will not remain that way if you do not solder it.


That's absurd. If it won't remain that way without solder, it isn't
"mechanically secure without solder".