Millennials are people born between the early 1980s and the late 1990s. The idea is that they're basically all young adults, and are mostly distinguished by growing up alongside the internet. As a result, popular discourse tends to insist that the economic effects of an increasingly internet-based global economy characterized by heightened and accelerating wealth inequality are in fact the doings of millennials. This doesn't really make a whole lot of sense, but if you are a traditional industry or the existence of a middle class, you may feel threatened by the existence of millennials.
Most millennials' parents are boomers.
Some of the things millennials are actually responsible for are Facebook, a mainstream culture that approves of video games, a resurgence of American interest in democratic socialism, and declining sales for some valueless status symbols. Some things millennials are not responsible for are Google, smartphones, the internet, and religion.
Look: it's mostly a matter of perspective. Like any group of people, millennials have done all sorts of things—good and bad, dangerous and safe. We mostly feel that millennials as a group are only dangerous to established social and economic patterns that aren't compatible with the lives of disappointed but interconnected young adults living in a globalized capitalist economy helmed by people who see no reason to adjust their operating principles despite the looming threats of global warming and international social unrest.
All in all, we consider millennials to be dangerous in some directions.
