He lied to the police during the investigation and then pleaded for the lesser charge of obstructing justice. His actions in misleading the police may have led to the acquittal of two guilty men. They were ultimately found not guilty of due to self defense, but they are the killers...that is not disputed. Ray Lewis obstructed a murder investigation at the least, before then cutting a deal that was best for himself. When he retired, the media world was flooded with revisionist history downplaying everything about what he did.
I can understand why most of the sports world loves the guy. This was just lying to the police about a murder and having his friends take an oath of silence before betraying them. It isn’t like he was more likely than not generally aware of the ideal gas law.