I mean, some of these do exist still. Don't get me wrong, the media blew them up tremendously, but still.
Atom bomb- the cold war was a thing
Y2K- Bit of an easy fix
HIV/AIDS- Still exists, but it's easily testable and avoidable
Colliding comets and asteroids- Not an immediate threat, and we're working on it.
Killer bees- still a very dangerous pest and can swarm people pretty easily, not to mention an invasive species, but you just need professionals and you're fine
Red algae- again, a potentially dangerous invasive pest, but easy to manage with professional assistance.
Global warming- that one is slow and nigh-unnoticeable without equipment or travelling around the world, but it's still a threat that we as a society face.
Ebola- Still dangerous, but we have treatments for it.
Water drought- California is still feeling its effects
Zika- Same as Ebola
E-coli- Really? This one is even less dangerous than Zika or Ebola. If the media blew this up, they're even bigger idiots
Black hole machine- we actually want to create a black hole to study it, because it'll dissipate in under a second due to hawking radiation.
Ozone layer- We fixed it by banning certain CFCs
North Korea- Again, still a threat, but we have enough firepower to make sure they stay in check.
Great Pacific garbage patch- Still a huge problem that we're working on.
Mad cow disease- Easily preventable and treatable
Trump killing us all- He might be a little unfriendly sometimes, but he's not going to get us all blown up.
The rest are even more idiotic and I don't have the energy to bash these guys any more.
Anyway, in conclusion, you are absolutely right and deserve an upvote, though we shouldn't trivialize some of these, as they're still major things we have to deal with. The media just kinda sucks at telling how imminent these things are, or how impactful, in many cases.