Hey, I've discovered that it's not possible to report a player that is blocking me. How can I report him?
It's not reportable. Blocking was set up to reduce disputes between people.
Anyone can block you.
If they were abusive before they blocked you, you can report them.
But otherwise, you won't be able to comment on threads they have started or will not be matched with them in regular games. (You might be matched in a tournament.)
Hey, I've discovered that it's not possible to report a player that is blocking me. How can I report him?