It's not that simple. They've lured me into spending a lot of money on their phones and tablets, and the iCloud and overall ecosystem was a very strong point in their marketing, and one of the major reasons why I went with Apple. Now that they've got me tied to their ecosystem, they start imposing unbearable conditions for continuing to use it, on the grounds that "you're free to leave if you don't like it". That's unfair to say the least.
Anyway, as I said, I don't object to Apple scanning what I send to the cloud. I only object to my own device, my processing power, my battery, being used for that. My own device is doing extra work for them. That's not right.