The current behavior here is deliberate.
You shouldn't post an answer to something unless you've read the other answers, how else would you know if someone's already posted your answer or not? While I'm all for encouraging more content creation from the mobile applications it doesn't make much sense to do that with the risk of degrading quality.
The only case I can really see this being useful is when posting on the formatting sandbox. It is however important to note that the website remedies this slightly by having pagination of answers rather than infinite scrolling. I don't necessarily think this is a huge problem but we can consider doing only one page of infinite scrolling them showing "Load More" buttons for answers in the applications.
For now however, this is going to be a status-declined.