Yes, is still there on mobile.

Where? I can only block them individually on mobile and it never saves. On desktop I can block and hide all guests with 1 click.

Where's this ban hammer on mobile? 

>Where?

When you are in the lobby, top left you can see the speech bubble, give that a click then you can see "Mute Guests" and "Mute Non-Subscribers".  Also, if you click on the players tab next to the speech bubble, there is an option to "Hide Muted Players".

Good luck.

Omg thank you! 

>Omg thank you

No problem.  Good luck :)