The notion that primaries are bad
is something akin to gospel in the Delaware Democratic Party.
Kos takes on this sacred cow in a post about Hacket/Brown in Ohio, and (surprise) I agree with him 100%.(In the 2004 election cycle) competitive Republican primaries in Oklahoma, Alaska, South Carolina, and Florida allowed those Republicans to use the momentum boost and media coverage to eventually win their seats. Democrats cleared their primary fields up and down the map for all the good it did (absolutely none).
This obsession with clearing fields really is counterproductive, generating a great deal of hostility and ill-will. And really, what better place to work on message and build the campaign machinery than in a primary? The primary election, at worse, becomes a test run to make sure the machine is firing on all cylinders. And the money used on media and whatnot during a primary is not wasted money -- it's a way to build up early name recognition to the electorate. It worked wonders for Republicans in 2004.
Now, insurgent candidates don't have a god-given right to respect or support. But if they want to run, then the party should stay the frack out of it. There is no legitimate justification for the price the party pays in meddling in such affairs.