DIP switches and DC-DC chargers

Endlessly replayed on reddit:

OP: I set the Renogy DC-DC charger’s DIP switches but it doesn’t work
Commenters: the DIP switches are wrong

OP: it’s not the DIP switches
Commenters: the DIP switches are wrong

OP: OK, the DIP switches were wrong and now it works.

DIP switches are fine but the present customer base has no pre-existing experience with them so confusion abounds.