Why does every app seem to have a low reputation?

Question

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.

Haridoss Sreenivasan · Answer

Hi Graham, 
 The reputation of an app is determined by the apps prevalent across the Sophos Mobile Security customer base, as provided by Live Protection telemetry data, SophosLabs detection data, and feedback data based on user actions. This user-driven feedback is collated and processed continuously to improve the quality of the reputation data. 
 Please refer the article Sophos Mobile Security: FAQ on App Reputation .