Cynicism is the bastard cousin of skepticism. While optimists look for the silver lining, cynics can't fail to see
the fly in the ointment and true skeptics are somewhere in the middle. Cynicism is an overwhelming trend in internet forums. The most upvoted reactions are usually the more pessimistic (regardless of factuality), and seemingly virtuous attitudes are immediately met with assumptions of bad faith.
Cynicism is tiresome and can very well lead to false conclusions.
This may be unlikely, but paradigms can be improved, governments can adopt better policies, corporations can act for the good of society, billionaires can be virtuous philanthropists, assholes can learn to be nice, and bigots can learn to respect diversity. We should be absolutely skeptical of sudden changes of attitude, but indiscriminate cynicism creates an environment that does not reward positive changes, and I don't think that's in the best interest of a community.
EDIT: I feel I need to clarify that cynicism is not equal to skepticism. Skeptics refrain from conviction in face of insufficient evidence, while cynics assume bad faith even without sufficient evidence. I am not advocating for naïveté, but for healthy skepticism.