McConnell gets to the top by two paths ~ one, he's actually liked by some of the other senators, not all of whom are RINOs, and, he's the least disliked Republican.
In a small body, being "least disliked" can be exceedingly important.
With or without RINOs (which in my book are guys who ever ran for office as Democrats, or who served as Democrat appointees, or who made important cash contributions to Democrats running for office (or for the Libertarians) ~ you know, like REAL RINOs, like ROMNEY and HUNTSMAN and..... well, you know, we had 7 out of the 10 RNC certified national primary candidates who fell into that category) McConnell would still be a contender for Minority Leader, or for Majority Leader.
This works over on the Democrat side as well. Harry Reid is the least disliked in a crowd of quite dislikeable people. Think of Chucky Schumer ~ NOBODY LIKES HIM! If Reid hadn't taken pity on him Chucky would never advance.
As far as sounding like "the chairman of the rino preservation league" may I remind you that there's an election that's going to be held this Fall ~ and you are up against people who really do want to know why you think it's so important for Indiana to GIVE UP top end seniority in the Senate where there will be a Republican majority?
Electing a new seniority deficient guy in the place of the guy with the most seniority is MORE SERIOUS than your ordinary election.
What is it that Mourdock can get that Lugar can't?
You really need to get that over to the Republican voters in the primary.
These are the same folks who scared off Evan Bayh, but that was then and this is now. Are they really happy with the non-RINOs you've sent to Congress? And are all those non-RINOs actually not RINOs?
The answer is, being conservative Republicans, we aren't interested in who can use the redistributive powers of government to best enable us to suck off of the government teat. So a candidate's vision of government should be more important to us than his time spent employed in government or his ability to give us "goodies"... right?