"Prudence, indeed, will dictate that Governments long established should not be changed for light and transient causes; and accordingly all experience hath shewn, that mankind are more disposed to suffer, while evils are sufferable, than to right themselves by abolishing the forms to which they are accustomed. But when a long train of abuses and usurpations, pursuing invariably the same Object evinces a design to reduce them under absolute Despotism, it is their right, it is their duty, to throw off such Government, and to provide new Guards for their future security"they should have added, "or if your feelings are hurt because someone said it's not good for you to own slaves, then it's totally okay, too."
You minimize and mock the very real threat to their financial interests. It is not radically different from Obama's threats to the coal industry. It was an attack on those people's livelihood.
It is furthermore an explicit and implicit assertion that they are evil people because of how they make their living. While this can be regarded as true after a fashion, it doesn't persuade anyone to change their way of making money. If anything, it hardens their resolve.
They find themselves in positions of having to convince themselves that they are not bad people and therefore they embrace the "badness" all the harder, because if they run away from it, it implies they were bad after all.
I think Northern Abolitionists behaved like, and were viewed similar to "Carrie Nation" scold types preaching against the sins of Alcohol. Most people who enjoyed it probably felt inclined to spite them in every way they could. In other words, by embracing it and drinking more.
Another apt metaphor is the anti-fur activists throwing blood on people wearing fur coats. It simply is a bad way to convince people that they are doing something wrong.