I would suggest this is a big nose-thumbing at the VDARE.com readership.
Just look at the Wikipedia entry on Bloomberg:
Bloomberg has attacked social conservatives on immigration calling their stance unrealistic, "We're not going to deport 12 million people, so let's stop this fiction. Let's give them permanent status." He supports a federal ID database that uses DNA and fingerprint technology to keep track of all citizens and to verify their legal status. Bloomberg believes that illegal immigrants should be offered citizenship and supports the congressional efforts of John McCain and Ted Kennedy in immigration reform. Regarding border security, Bloomberg compared it to the tide, stating, "It’s as if we expect border control agents to do what a century of communism could not: defeat the natural market forces of supply and demand... and defeat the natural human desire for freedom and opportunity. You might as well as sit in your beach chair and tell the tide not to come in. As long as America remains a nation dedicated to the proposition that "all men are created equal, endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness," people from near and far will continue to seek entry into our countryBasically, McCain is hoping that with a few symbolic arrests of illegal immigrants themselves, a big chunk of the political base will forget in November that a huge, nation-changing amnesty is the official policy of the GOP.
Now, I won't vote for McCain regardless of who he picks as his VP. I can understand why a lot of VDARE.com readers may find much more in common with McCain than I would-and I can see why they might consider risking a McCain presidency if he picked someone like Pawlenty as his running mate, who has spoken somewhat sanely on the topic of immigration.
Regardless of McCain's VP choice, Obama's optimal election strategy is to pick someone less cosmopolitan-and more working class than himself. Obama already has a lot of electoral funds—and just doesn't need the "juice" Bloomberg's support would provide. If Bloomberg does run with or endorse McCain, Obama's optimal strategy may be to choose a running mater like Jim Webb—and pursue populist issues much more aggressively.
The thing is, if McCain picks someone like Bloomberg as his running mate, it is in the interests of Paleocons to see McCain defeated as decisively as possible—say with a defeat worse than that suffered by Goldwater. That might at least delay McCain's ideology from rising again for several years.