Well I think I found a trend for my reviews on Amazon.

“I was a bit put off by the use of italics for slang words, but understood that it was to emphasise that the word was slang for the roaring twenties.”

–and–

“I couldn’t get past the first few pages because of all the random words that were unnecessarily italicized. Really drew me out of he story and made it impossible to read.”

I got the hint. Just had all of those italicized words removed from my manuscript and uploaded a new version to Amazon, Smashwords, and Draft2Digital. Fortunately Microsoft Word made that operation fairly painless!