Negativity and Attrition is a part and parcel of every single customer or campaign audience you encounter.
The secret sauce to make sure it doesn't affect your brand is to do a customer classification matrix based on their potential and engagement towards the brand.
This classification will help brands to focus their resources in the growth areas and manage the brand strategically with the existing customers.
Always have a close watch on high potential customers with high and low engagement. They are your gateway to success. If negativity raises out of that faction, be agile about it. Always aim for their higher engagement with the brand.
The other side of the spectrum would be low potential customers with varying engagements with the brand. The key is to maintain and manage them and be smart about altering strategies with respect to the cohorts. There is no harm in losing bad customers and freeloaders.
Aim towards maintaining a gold brand standard and at not being in a position that makes your customers/audiences dictate them for you.