I think a lot of people were a bit miffed, not because JW made the comments (or figuratively shot a collie) but that Obama said that he didn't say anything divisive in the 20 years he knew him and that he was his mentor. And that the pattern of hate of America that JW shows was also visible, to a much lesser extent, though still visible, in his protege. I don't blame Obama for his pastor's stupidity. I count it against him for lying about it and wonder if he hates the country that he wants to lead as much as those around him say they do.
We didn't even talk about Bill Clinton's or George W. Bush's pastors when they were running for president and I don't think most people even knew or cared about them, if they even had them. If those people had interjected themselves into the fray, I'm sure people would have asked, rightly, how their pastors had influenced them.
But I imagine that if Bill Clinton's pastor had killed a collie, he wouldn't say that he learned so much about how to treat dogs from his pastor and that the pastor never so much as mentioned killing dogs when all along, the pastor had been saying from the pulpit that dogs were the evil of the world and that he was just hoping one day a dog would run out in front of his car. Nor, upon further scrutiny of Clinton's dog hating ways would he have worn an "I hate dogs" lapel pin. Clinton was just too smart for that.
Hiring a president is a really big commitment. Many of us want to know just who we're getting into bed with. Especially after the last 3 prezs and 20 years.