From memory, you definitely were able to install root certs pre-7.0ish but that functionality was removed, presumably to stop users from running man in the middle proxies and sniffing app traffic.

A huge irony in that alongside all the talk of conservatism, iOS provides much more user flexibility in this area of all things, and something that keeps me using the ecosystem.

You can still load root certs but as mentioned, it requires rooting your Android device. Some apps do have certificate pinning but the majority I would bet don't