Hemingway didn't write very Hemingwayish. That is, he didn't write the way many people caricaturize him. He has a big vocabulary and can, in fact, create more than a 5-word sentence.
That being said, "utilize" is one of my peeves, too. "Utilize" rather than "use" and "gift" as a verb. We hates them, we does.
This is the key point. He tended to use active voice, single clauses, and simple words. None of that is the same as small sentences and a limited vocabulary.
His approach was as simple as possible, but unlike what this app creates, no simpler.
That being said, "utilize" is one of my peeves, too. "Utilize" rather than "use" and "gift" as a verb. We hates them, we does.