It is one essential part of the ability to think independently. Without it we would probably still be in the dark ages, believing the infallible dicta of another church. If Copernicus had not doubted dogma he would not have disproven the idea that the heavens revolved around Earth. Gallileo could not have discovered the beginning of modern physics had he not been skeptical of church sanctioned beliefs. Scientific methodology could not exist without skepticism.
Skepticism helps to drive discovery and change for the better.
Obviously well-intentioned people would encourage reasoning skepticism. This is certainly true in my personal experience. After all, skepticism would be dangerous indeed to a lofty-sounding but false and useless dogma. Inform oneself honestly of the actual intentions and activities of that group, project or organization, brushing aside all bias and rumor. Examine the statistics of the individual, group, project or organization.