Irrelevant. You claimed that by simple virtue of his bringing a gun to the protest that he went there with the express intention of shooting someone. If that's true then it's also true of Grosskreutz and everybody else who went there armed.
You should know (if you don't know already) that Grosskreutz has a criminal record, two arrests of which were firearm related.
He has been arrested twice for possessing a firearm while intoxicated. In addition to these he has been arrested for and/or convicted of domestic abuse, prowling, trespass, two DUIs and felony burglary.
It's ironic that for all the vitriol and demonization of Rittenhouse for bringing a gun to the protest, Grosskreutz was the one who actually violated firearm regulations. Not only did he have the two arrests for firearm possession while intoxicated as noted above, his conceal carry permit was expired the night of the shooting so he's the one who was illegally armed.