A Marketing Equation:
Marketing Effort + Effects of Positive Opinion - Effects of Negative Opinion = Marketing Effectiveness
In business communications, there is little recognition that, typically, a significant percent of the market doesn't think well of you and may even hate you. Many will do anything they can to drag you down.
In Net Promoter terminology, that percent comprises the detractors. If your organization were a sailboat, your marketing attempts would be slowed by dragging an anchor of negative opinion.
If 20% of your market has a negative opinion of your brand and each person shares that negative opinion with five others while the 80% with a positive opinion each tells only one other person, within a short time the market will be more negative than positive.
New prospects coming to the market will more likely hear negative things about your brand. Current customers, even those with a positive opinion, will either shift to defending you or just shut up. Negative opinion poisons your market and your ability to clean it up.