I think our point of disconnect might be coming from the issue of elected office versus political party affiliation. The primaries are the means of electing someone into or out of elected office. Party affiliation is the domain of the RNC or the DNC. They're not the same thing.
I don't know if that helps either of us resolve the disconnect we seem to be having or not.
“Party affiliation is the domain of the RNC or the DNC.”
Wrong. You dont have to go to the RNC to file as a Republican. You could be a lifelong Republican and file in a Democrat primary, nobody can stop you. A blatant liberal Democrat filed and won a GOP primary here in Texas to frustrate the republicans. He had a safe-sounding name that was the same as a real Republican running that year.
The ONLY thing you can do is get them defeated in elections. Short of that would be a refusal to caucus with them or deny them committee assignment; and short of that is what I proposed - censure resolutions.
And btw I put my money where my mouth is on this - I supported Toomey in the 2004 GOP primary. Close but no cigar.