Yeah, but my memory of The Twilight Zone and The Outer Limits is not that they had a particularly pessimistic or dim view of humanity, just wildly imaginative views of a Universe perceived as dangerous.. In fact The Outer Limits tended to deliver human grace and courage on the part of at least one of the protagonists at the climax just about every week. They weren't bleak or nihilistic shows for the most part, even though Serling loved the sucker-punch..
ZONE and LIMITS were anthology series, of course, so some stories were more pessimistic (or optimistic) than others. Humanity doesn't come off looking too good in, say, "The Monsters are Due on Maple Street" or "The Shelter," while post-nuclear war plots were common, even if some had the survivors trying to get by as best they could. Still, just the fact that post-doomsday scenarios were a stock element says something about people's fears and expectations back during the Cold War.
More often than not, though, TZ often reflected reality by showing both the good and bad sides of humanity. See "The Obsolete Man," "Night of the Meek," "Steel," "It's a Good Life," etc.