It's not up to fans to determine who goes into the Ring of Honor. Fans trying to gatekeep is insanely dumb. The man was cut and played well for the Niners; Sherm is allowed to be a fan of both teams since he played for both.
Also remember Sherm is trying to build his post NFL brand, like it or not. Plus I think he likes playing the role of the heel. He’d be an excellent bad guy if he ever got into rastlin’, as he knows how to push people’s buttons and get heat.