Was Sheldon justified to enter the room when Missy was upset?

I see a lot of debate surrounding this scene. Just curious about what everyone thinks. Personally, I think Sheldon was justified in entering. Legally? yes. Emotionally? No, because if one of your family members needed space then a good sibling would give them their space. But there was nothing anyone could have done to legally stop Sheldon from entering his room. Now I’m not talking about Missy ripping up Sheldon’s poster, because I think most people can agree that it was Sheldon’s fault for coming in and making rude comments to Missy. I’m just talking about Sheldon entering the room in the first place. It’s still half his room and Missy cannot deny access to his room just because she is having personal boy problems, so I would agree with Sheldon ignoring Missy’s sign on the door and being allowed to enter his room whenever he wanted. Lastly, George Sr., the owner of the house, said “You don’t wanna go in there”, not “Don’t go in there”, meaning George Sr. recommended Sheldon to not enter the room, not prohibited. So legally Sheldon was fully in the right to enter the room, but it was his fault his poster got ripped up. What do you all think?