What the national republican leadership did in your state was reprehensible. It is clear that a substantial majority of republican voters wanted a change and under the existing election law were denied that change by crossover democrat voters. I understand your frustration and anger but would respectfully suggest a different course in response.
Since your side is clearly a majority of the republican party, rather than electing a democrat to a six year term, it would be more productive to mobilize your majority to change the election law to eliminate the open primary system. The state representatives and governor would find it very difficult to resist this needed reform if faced with a determined majority of their voter base. With a closed primary system in place, future primary elections could not be hijacked by crossing party lines.
I am not as close to this issue as you, but it would seem to me that the people who perpetrated this injustice would love to see those of you who oppose their control withdraw from the process. I would rather take away their power to manipulate the system than to let them have their way. Your group clearly are a majority of the party; don’t let the rascals run you out of your own party.