wow you're right! It does turn it off. 
The only issue is the Public Outbox which is the first relay setting, you can't turn those off in the global settings so they still show up in the global feed even though I turned it off in the last relay setting.

If I keep only 1 or 2 relays in the public outbox it might work better. 

This will be useful thanks.  

 interesting. I'll play around with it.

@Vitor Pamplona any idea or thoughts on this?