If your hypothesis were true, we wouldn't have been able to point out to you the several ways in which the jury did not hear all of the information, and was not allowed to consider any evidence as to Kyle Rittenhouse's possible motive for shooting people outside of the events of that night.
We wouldn't be pointing out the places in his testimony where Kyle implicating himself as the instigator of the violence which followed, or anything that would demonstrate that Kyle was one of life's little shitstains, before he bought that illegal AR15, and then immediately went out and killed two people within it within 24 hours of acquiring the weapon.
There is no way you can show that Kyle went out hunting leftists that night, without looking his words and behaviour leading up to that night. When things weren't "wild enough" for Kyle where he was, he left the private property he was supposed to be protecting, and went looking for trouble.
He entered areas police told to stay out of, and admitted he was afraid to be on his own in the crowd. The trigger happy little thug was inclined to shoot first, regardless of circumstances. He turned and fired on Rosenstein without a second's hesitation to consider the situation or whether he was in any serious danger. That's how frightened he was after the protestors called him out for pointing that gun.