I agree -- Republicans in name only continuously attack Republicans and conservatives, and are doing it to undermine the Republican party. They are not very secret agents for the enemy.
Years ago their line consisted of buzzwords like "neoconservative" and "RINO"; now it's more likely to be "uniparty" and "GOPe", and contain statements like "I'll never send the Republican Party another dime".
As you said, they're "purists". They refuse to consider any conservative, because that's what they're all about -- rejecting conservatism. They operate online in order to undermine all opposition to the Party of the Single Party State, the ill-named Democratic Party.
No matter who is the nominee, their job is to pretend to be conservatives and Republicans (or former Republicans) and attack the nominee as hand-picked in a fictional process.
Bonehead and McConnell and Romney etc are leading the Republican Party to the left. It has become nothing more than a little “me too” sister to the Democrats.
Look how fast the GOP jumped onto the anti-Confederate flag bandwagon!
I won’t mind if the GOP ceases to exist. It doesn’t deserve to have my vote.