The issue is the developer. React-Native as a tool allows you to make poor design decisions, but it does nothing wrong itself. We need to be vigilant and remember to stick to native interactions.
With React-Native, it's really easy to be lazy. If you want to be on Android, but you don't want to change your designs to fit Android's UI standards, screw it, just write a wrapper around some of the iOS components and call it a day.