what Is the point of this forum?

For players to talk to each other? Forums are there for community discussion.

I presume you mean the Player Behavior boards - the point is for the community to discuss punishments. The point of this board is not for players to appeal bans to Riot, although if a player's punishment gets enough traction and a large portion of the community feels it was unwarranted, then Rioters do step in to either rescind the punishment or inform why the punishment was placed.

The point of this board is to help people understand their punishments and for players to discuss potential changes/improvements to the punishment systems, not for players to appeal bans. Riot involvement is not necessary except in extraordinary cases where an idea or a thread gets an extraordinary amount of attention from players.