I did not see anything in the video I have seen to indicate that the deceased was attacking anyone. This is an attempt to undercut the defense of Kyle over actions taken in legitimate self-defense in Kenosha, or distort the notion of self -defense so the rioters can hide behind it.
That might not work so well if they succeed in lowering the bar for 'self defense', because if one person who might disagree with you is in a crowd of people and fair game, rioters a block from your house could easily be seen as a threat to your life, safety, and property, and could be removed from the equation from any high point on the property "in self defense".