I think regardless of whether or not "stand on the right, walk on the left" (or some equivalent), it is never rude to walk on an escalator and politely say "Excuse me" to pass somebody, assuming that the escalator is wide enough to do so safely.
This brought us back to the OP's etiquette question which was essentially, "was I rude?". I agree with MariaE, whenever someone is in your path, politely saying "excuse me" and giving them a moment to move aside where there's room, is not rude.
As other posters have mentioned, however, many escalators aren't wide enough to fit two people one one step, AND, escalator manufacturer OTIS instructs to stand in the center of the step, not to either side, for very valid safety reasons. I think escalators are so prevalent in modern times that they've become part of the scenery, and people forget they are indeed standing on moving heavy machinery, which is always a risk.