We spent today doing an audit by revisiting recent issues reported to abuse@matrix.org, which had already identified and acted on the content in question. We also took the opportunity to explain how Element and Matrix fit together, what decentralisation is, and the steps we take to mitigate abuse on the servers we run.
As a result, it looks like the app has just been reinstated while I was typing this message: https://play.google.com/store/apps/details?id=im.vector.app.
Thanks everyone for your patience and support while we sorted this out (and huge thanks to the overall Element team who spent their Saturdays on the audit).