You just have to retrain your brain.
The issues you are experiencing stem from Apple and Google's respective schools of thought.
Google
Usability is more at the forefront because Linux is inherently more secure than other operating systems. That argument doesn't necessarily stand up to iOS but when you think about the myriad of malware and computer viruses, there is constant pressure from media and consumers to ensure the safety and viability of a platform from hackers. You are given options to share from core Android apps because of the open source nature. It is what differentiates Android from the competition.
What works for Facebook, Vine, Twitter also works for many third-party applications. You could see this as competition and a relatively good thing, or you could see this as opening the floodgates and allowing for potential trouble down the line with poorly coded software.
Apple
Security, while important, doesn't take away from usability. Instead of being in the Gallery and having a plethora of options for sharing, it is pretty sparse. This is done to not overwhelm a casual user, and to ensure a layer of security that apps aren't just nestled in your preferred list of sharing programs just because one time it made sense to do so.
Open an app and share within that app. You can't tell me you were posting to multiple services at once with one click.
It's a bummer, but I hardly used the share from in the Gallery to post outside of a core app. It was just easier to use Facebook, Twitter, etc.
You just have to retrain your brain.
