I don't want to jump into the fight (above) about "who is right" and "who is wrong", however, from a human factors perspective, it appears to me that it would make a whole lot of sense if the manufacturers of twin engine aircraft standardized on "right and left" as the nomenclature for engines.
The aircraft I specialize in (Twin Otter) uses right and left, however the Dash 8 - also a DH product - uses 1 and 2. Perhaps this is because DH produced the 4 engine Dash 7 in between these two, and they didn't think too carefully about the nomenclature when they did the labelling for the Dash 8.
"Port and Starboard" are terms that seem to slowly be evolving into archaic words - we inherited them from the nautical world, and few new pilots who do not have previous nautical experience are familiar with the terms. On the other hand, everyone knows what left and right refer to. The flight attendents are likely familiar with which side of the plane is left and which side is right, regardless of which way they may be facing when they are seated.