All the non-believers and non-spiritualists are blamed by religious believers to be following the negative philosophy. It is said that who are not going to church / mosque / temple everyday are looking at the negative sides of life and not following the correct path.
My assertion is that Non-believers were like this always. We always liked not to follow any set path but just do the living. What happened next is that people could not face life's increasing difficulties in increasingly complex world. They then went ahead and created some imaginary figure where they can turn to when no answers are available to them.
Ultimately few others came along and they decided to show people how to find their correct path at some point in time. so, 2000 years back, Jesus shown the way. That way solved the problem of those times. Now the people who were looking to imaginary gods suddenly had a living icon and they converted that icon to god.
His path may have been partially true even now, but it needs to be modified by equally brilliant person as per the current demands. This is where non-believers choose to disagree. They want old path to be corrected to reflect current realities while believers still follows 2000 old sayings. And because non-believers have chosen to question this old 2000 year old theory, they are branded as negativist.
With the same yardstick then, even believers can be termed as the negativist. They are not ready to change and so trying to stop the flow of thoughts.