I think it would be very naive to store unencrypted your pirate movies, music and tv series with a company that sells movies, music and tv series.
Amazon, the same company that treats its employees like slaves (search for “the truth behind the click” if you want to see what its like to work for them), undercuts real businesses by selling at a loss - often forcing them to close down, all while paying no tax themselves.
So yes, lets trust Amazon to do the right thing.
One provider I did stumble over while reading up on this subject last night is OVH, they offer a service called Hubic which is 10 Tb for €50 which seems reasonable. They dont have any conflict of interest (selling media themselves), there is a hard limit rather than the pretend “unlimited” which everyone always knows isnt really unlimited. Even so, I would still encrypt anything stored in any cloud, but with them it seems more like a thing to do for peace of mind rather than an essential requirement.
Edit: Just started reading some reviews etc about Hubic before signing up. They have limited the speed of it to 10 Mbps, which is a shame but doesnt totally kill it.