Yes, but they don’t have to actually support the candidate that comes out of the primary.
If the state party made it clear that this scumbag wouldn’t receive full support, the primary voters might not have put him on the ballot. I remember Republicans speaking out against David Duke when he tried to use the GOP’s good name to further his own ambitions.
Blame the voters. They had a clear choice. Most voters know little. Voters would vote for Satan if they believed Satan could make the economy hum on all fours. I really believe that.