General Discussion

has alienated many right wing groups for different reasons, to the point where they avoid Fuentes' purity confrontations. Yes, Fuentes' stalking them makes him look bad, but it also makes his froggy followers in their moms' basements feel powerful.

And though I do see Robinson's motivation as ideological along Groyper lines, I can't see any direct connection between his killing Kirk and Groypers at large.
My gut theory is that even though Fuentes had attempted confrontations with Kirk, the shooter himself likely didn't represent Fuentes in deciding to kill Kirk, nor did Fuentes or other Groypers suborn Robinson.

Unless Robinson says under oath that he was both motivated by Groyper ideology and was directed by any Groyper to kill Kirk, I can't see any coconspirator evidence that would either enhance or mitigate any charges filed against the shooter. Which is why his family knew they alone had to come to his aid and get his defense prepared.

I could be wrong...
Just thinkin' out loud here, because your OP about their environment is really important. So again, thank you.