However, put yourself in Sheldon shoes. In his mind, he is tired of being accused of stealing just because he is black. So he thinks, ah this time I have proof. You know what? I am going to make a big scene first before showing it.
I know a guy that was scammed by a big corporation. The guy buys insurance at the price of 100 times the cost of typical kinds of stuff. He could have shown evidence.
Everyone thinks he doesn't read the contract carefully, doesn't ask agent enough, trusts the sales agent too much.
No. Sheldon asks for "explanation" publicly first. The company anonymously send an agent repeating some misleading sales pitch. Then someone else shows evidence, but it doesn't get big.
In Sheldon's mind, it is wrong to suspect someone for being black. In the spirit of the guy, it is wrong to scam customers.
However, what we think is wrong, is often different than what I think it's wrong.
To me, it is not wrong to be racists or prejudiced. It's your mind. It's not good. It's not wrong. Libertarians think that we should resolve this by the market mechanism.
People like Sheldon believe that societies should solve this via suing or via war.
In the eye of the white guards, these black guys will bring problems. They are trouble makers. And Sheldon shows that again, it's true.
One possible solution is things like reasonable reasons to believe. Do the guards have rational reasons to think that Sheldon is stealing? Yes.
Is it okay to be wrong if you have understandable reasons to believe you are right? Wow. Declaring something is right even if it's wrong because there is a reasonable reason to believe is a very slippery slope.
We have religions, prejudice, and ideologies giving understandable reasons to believe wrong things.