As far as I know it's because at higher leagues Supercell intentionally hides the opponents names to prevent cheating! (Friends might recognize each other for example)
Wtf bro just played 4 matches and got from Legendary 2 to Legendary 3. While it took me a whole week just to go from Legendary 1 to Legendary 2. How unfair.
Bro you are legend you did Masters.It is very hard.I played with sus randoms and I am mythic1.And i need some friends with masters or good gameplay.Please send me friend request.ID:YJV0PL8VG