You're justified in being shot if you try to physically attack them by repeatedly hitting them in the head and then trying to grab their gun, yes.

As far as everyone knew, Rittenhouse was a shooter (that’s a risk you run carrying a rifle)

What were they supposed to do, let him flee?

Ah yes, the only two options here were to let Rittenhouse flee and to repeatedly bash in his head.

I only wanted to let you know what the argument was.