Caitlyn is anti-fun

Not saying she's op (which she is, but that's beside the point). She is a bully at every stage of the game. She pokes and prods at you, and you can't fight back because she does it safely from her massive range. Her traps are the most oppressive part of her kit though. They cannot be disarmed without eating a huge crit.

Let's look at another extremely safe ADC: pays for his safety through his damage. He has a power trough during his tear stacking. He doesn't have good AoE and deals less DPS than other ADCs. He is balanced.

has some of the highest damage and scaling of any ADC. She has the longest auto attack range. She has an escape. She has the best zoning and control of any marksman. She has no weak point.

All of this amounts to her being picked every game and sapping the fun out of it.