Focusing/CC isn't counterplay

I had a discussion with a Fizz player (who admitted Fizz is broken) and his justification for no Fizz changes is that Fizz can be shut down and CC's before his W can be proc'd. I still don't get why people consider "oh just CC them and collapse as a team" counterplay. By definition, it means that a champion has no counterplay and just needs everyone to throw everything they have at one champion. But guess what? If everyone burns cooldowns on one broken champ, suddenly the entire enemy team can throw everything they have at everybody instead of needing to focus one champion. The balancing team needs to just stop being lazy and tune numbers so that a champ is still powerful, but isn't completely unpunishable.