Mute All Players On All Games

Only thing i can find is in your profile - privacy settings - there are a number of privacy options such as child teen adult or custom , it looks like the child and teen settings stop you receiving and hearing others , other than friends, cant say for sure but you could try then change if no good . Other than that it will be only at the begining of each lobby doing a mute all (which quite frankly will be a pain- and awkward if trying to protect a child) therefore i am thinking the child setting should stop hearing randoms.

Let me know

sorry for multiple posts - but i have found the best way , you do it via your pc , go to top and go into friends at the top of friends it says

On Xbox One, friends have evolved. Learn more below.

Manage privacy

click the manage privacy green writing

this takes you to the options of who can see your stuff and who can hear you and who you hear

on others can option you want to set this one to block

Communicate with voice and text (Xbox 360: Voice and Text)

Decide who can communicate with you using voice and text. Please note: Skype uses separate contact permissions, which must be managed in Skype.

This setting is about who you want to communicate with. To block or allow communications on a console, check the online safety settings in the other tabs.

this should sort it x