They were there to intimidate Governor Brewer and those citizens of Arizona who support her efforts re: immigration.
Speaking of which, if this wasn't a campaign rally, why was she BOOOED? You don't booo people at a funeral. For me this was the tell tale moment. You might be able to give lame excuses for t shirts, and other junk, but the boooing. Boooing has no place at a memorial service.
That was no memorial, it was a stump speech.
BINGO.