Politics is often about perception and labels. The Democratic party is quickly becoming the party of immorality. While commentators won't openly declare the Democratic party as immoral, they have no problem declaring Bush voters as "values" voters. So simple logic leads to the conclusion... if Bush voters (Republicans) are moral then Democrats must be immoral.
The Democratic Party can not lose the battle over this word. Democrats must use the "m" and must use it often, but it must be defined on their own terms. Democrats must define morality as pro environment, pro civil rights, helping the poor etc.
This battle is huge, and it must be won. If not, the Democratic Party will be wearing a scarlet letter for a generation.