This blended or portmanteau word seems to be gaining ground fast if online news and websites are any indication. Obviously it is a mix of sheep and people and describes the masses that are easily led, relatively unthinking and undiscerning. Conformists and obedient.
Let’s put the mistake the army made with the bomb down to terrorism and the sheeple will believe it.
Taylor Swift started wearing lederhosen and, like sheeple, all the teenage girls and boys have gone out to buy a pair.
There is an older term “lemmings” which was in fairly common use.
Whatever the head of the club said, the fans went and did it like a bunch of lemmings.
Apart from the fact that most people have a very vague idea of a lemming (it is a rodent, similar to a vole), the characteristic of being a lemming was rushing blindly into destructive behaviour like throwing yourself off a cliff. So I guess being likened to a sheep is a little more benign.