I am a fan of Howard Dean and I disagree with your perception...

Your rant missed explaining why the blue-dog Dems tend to be the the first and loudest to condemn and disrespect the liberal base all the times; why they are the first and loudest to go against a Dem president when he pursues core liberal agenda but slow, if ever at all, to stand up to reThug president when they push their crap; why they are the first and loudest to rubbish the Dem platform if they disagree; why they are the first and loudest to jump on the bandwagon of the reThugs and Teabaggers whenever they perceive that issues are getting hot.

The claim you make that reThugs welcome all sorts in the midst overlooks the fact that so called moderates in reThuglican party hardly do similar things to their side. Even when the reThug moderates have disagreements with their party/leaders/president they tend to deal internally with them and show united front in public or don't vehemently show their opposition as such in public like the blue-dogs always do

Tell us how much the reThug moderates did to show their disagreement on ACA despite stringing the Dems along while ACA was being put together or during the debate? Tell us how much the moderates rebelled against the reThug leadership when government shutdown was being threatened and eventually imposed on the administration?

I think the key issue why the blue-dogs are disliked by some on DU, IMO, is that they tend not to have regard or want do much for the party when things get hot; and so are seen as politically selfish, disrespectful to the party, and eager to sellout the base for their own financial gain.