Also, what do these cops and government officials say about iPhones? iPhones, according to what I've heard, also have good privacy, is that not true? Is it not private enough for criminals?
By default, iMessage conversations are backed up iCloud with keys Apple has access to. Governments simply have to ask Apple nicely for the data, or serve them a warrant/subpoena/court order/etc. Apple has a web portal to automate this for them because of how often they share data.
For a while, iOS zero days were cheaper than Android exploits because they were so plentiful, but it looks like prices for iOS and Android exploits are about equal now, suggesting both platforms are similarly exploitable.