Basically what Kyle Rittenhouse did is clearly self defense.

However, he is carrying a gun against the law. So he cannot claim self defense.

Is this true?

The reason I ask is I thought that the criminal activity must be related to why he is being attacked.

For example, a burglar comes in to my house and I shoot at him and he kills me. Now he's committing burglary.

However, Kyle's crime is bringing a gun illegally. He doesn't rob or burglar people. The fact that his gun is illegal has nothing to do with why people are attacking him.

How related is the crime of those who claim self defense for this rule to apply? For example, say I park illegally and someone tries to rob me and I kill him. Can I claim self defense?

Or say an illegant immigrant is peacefully enjoying dinner. Then someone robs him and he grabs a nearby gun and kills the robber. Can he claim self defense?