GOP frets about swing state toll on Romney from Bain attacks

Republicans are beginning to look with trepidation at the Obama campaign’s all-out effort to turn Mitt Romney’s business experience into a political liability, particularly in corners of the country that could decide the November election….The Obama campaign’s line of attack versus Romney found its origin in the Republican primary, when Romney’s opponents charged him with perpetuating ‘vulture capitalism’ during his time at Bain Capital. They pushed him to release years’ worth of tax returns, which the Obama campaign is now demanding as well….Though the Obama campaign endured a measure of friendly fire from Democrats (who questioned the wisdom of attacking Romney’s private sector career) since it revived these attacks for the general election campaign, they largely haven’t let up in their scrutiny of Romney’s Bain record.

Can anyone tell me why some Democrats thought attacking Romeny’s predatory venture capitalism (which is what venture capitalism is most of the time) was a bad idea other than they take money from same? (real reason I think). In any case I am glad Obama stuck to his guns on this and did not listen to Bill Clinton.