The point is, an ion engine is not some aspect of the universe that may be wrongly interpreted by contemporary physics. It is an established bit of engineering. Having sci-fi characters punch a hole through an armored steel wall with hand-thrown tennis balls would be equally ridiculous.
I do concur that the widespread notion of an "ion drive" had been the electrical acceleration of ion
ized particles for propulsion exhaust.
At the time it was and sounded admittedly like a more sophisticated (and cleaner) from of propulsion than the nuclear one, but apparently many people didn't understand that the thrust of such an ion drive (only works in the vacuum of space) is ridiculously inferior to even a chemical rocket (it builds up velocity over a long period of time and simply has a better payload-onboard fuel ratio).
The "official" interpretation for the acronym T.I.E (fighter) is "twin-ion-engined" but already a quick glance at the stern of Lord Vader's (long range) TIE fighter reveals that there are not two but four propulsion
Many years ago I talked about the issue with ILM model maker Lorne Peterson in Italy and he told me that they had considered an alternate acronym interpretation: Thermal Ion Energy
Considering that nuclear fusion occurs by the free floating particles of an ion
ized plasma, I had always taken this as a very strong hint, that we are looking a two fusion reactors powering the TIE fighter which are somehow referred to as "(power) engines" opposite to "(propulsion) engines".
Though I usually abide to the unwritten law that you shouldn't mix terminology of the Star Wars Universe with the one from the Star Trek Universe, I'm afraid, that the "ion power" quote from Scotty in "Spock's Brain" equally refers to some kind of fusion process.
Maybe they used antimatter deuterium and antimatter tritium for antimatter nuclear fusion which still might be somewhat more what Federation technology is capable of in the 23rd Century.