Why does every app seem to have a low reputation?

After the latest update (8.1.2647 on Android 7.1.1) almost every app I open prompts a "low reputation app" warning.  This includes my banking app (Nationwide) and LastPass password manager.

There were previously only a few low reputation apps, and I was happy to make a call on whether I trusted them or not.  Has something changed?  I feel like I need to deactivate this option, because it doesn't seem to serve any useful purpose if it doesn't trust anything.

Thanks,

Graham.