Why do Democrat supporters pretend that the Northern Democrats were good, when 100% opposed impeaching Democrat Pres. Andrew Johnson?

The Northern Democrats of the 19th century were not necessarily perfect, and they certainly opposed the impeachment of President Andrew Johnson, but they were also responsible for major legislative accomplishments such as the Homestead Act and the National Banking Act. The Homestead Act provided public land to settlers in the West, while the National Banking Act allowed the formation of national banking associations to create a uniform currency. These acts were instrumental in helping to get the nation back on its feet after the Civil War. Furthermore, these Northern Democrats set the standard for bipartisanship by setting aside their differences for the greater good. In other words, the Northern Democrats are remembered more positively due to their successes in promoting a unified nation with a strong economy. Despite their disagreement with impeachment, their accomplishments should be seen as far greater and are more worth focusing on.