You can opt out of NSFW content in your account on each instance. I think you've identified a need for us to add an override option on the app to apply when you're looking at content from servers you've not logged in to, is that right?
You'd be more than welcome, and don't feel shy about picking through the code for ideas and things you'd like to do better! We'd welcome any suggestions or contributions you make.
There's some options in Settings you might like :-)