He was banned against Werlyb only because Jax is his signature champion and he's not able to exert a lot of pressure on other champs. A lot of players have their signature champs banned; ie, Freeze's Draven, Faker's LeBlanc (back before nerfs), Deft's Jinx.
Jax isn't worthy of ban status at all. It's true he's not trash-tier, but he doesn't deserve play in LCS, much less bans. He's a decent pick, but just realize that the Jax bans were targeted at a certain player rather than designed to remove a broken pick from the game.