No, Data is not a machine. He's a sentient being with a neural network analogous to a human brain. An amoeba is a biological machine acting out a simple series of preprogrammed behaviors. A human being is also a biological machine, but that doesn't mean we can be validly compared to an amoeba or a housefly or some other vastly simpler organism. What matters isn't whether his physical substrate is naturally evolved or artificially constructed; what matters is the structure of his brain and the nature of the processes that go on within it. Cognitively speaking, Data is far more analogous to a human being than to a PC or an iWhatever.
What's fundamentally inept about your analogy is that your computer can't use
contractions. It can spit out contractions when programmed to do so, but it can't decide
to use a contraction or understand what it means. It's just processing numbers that correspond to patterns on a screen that our brains can recognize as letters that spell out a word we understand as a contraction. There's no actual cognition involved, no choice. The decision-making was done by the human beings who programmed it to follow certain algorithms. Data, by contrast, is actually thinking, choosing words with awareness of their meaning. That entails layers of cognitive processing, comprehension, analogy, and abstraction of the sort I've been discussing. It's a completely unrelated thing.