All of the "easy" champions you mentioned are easily countered w/ the exception of maybe Darius in TT, but really you just need to zone him out and you'll be good.
The other champions or what we'll call.. "Niche" champions are generally less viable in a game without the clearly defined roles and actions required in a high-elo ranked game. They tend to be counters due to their kits or items or are intended to fill a specific role.
With the ones you did mention, there isn't a "Niche" that they need to fill. They are sort of decent all around champions. This makes perfect sense... Because they don't need a certain enemy or ally team comp, or certain situations in order to be viable they are good picks for pub games, especially with the minimal champs in TT.
Unfortunately, you are viewing them as "easy" characters...when in actuality they are simple blanket viable in TT. If you don't need a special situation to be viable, you instantly become more viable that someone like say Oriana who needs a strong initiator to really shine.
If you want to play more of a Niche champion, no big deal, as long as you can maximize their viability. But, you can't blame people for taking a champion that is generally viable over someone that needs more specific exterior factors to fall right in order to be successful.
Base line that any summoner wants is to win the game. Sure, I'd like to win with a super nerfed out character and still pwn noobs. But, it just isn't as possible. So, generally, people will pick the characters they think are the easiest to win with.
The big caution here is that the champions you listed are not at all "win buttons". There are simple and easy champions that will counter these guys without too much trouble. Point being, just because the "community" identifies them as cheap champions, doesn't mean they are actually any better than anyone else.
A great example is Trundle. You don't see a ton of him, but when you do..he can be a g'damned menace. He isn't considered OP, but he has a very nice kit that is simply underutilized.