They know he will soak up all of their dmg and yet they still can't help themselves...
I'm starting to think that Rito gives tanks a mental taunt that makes the player focus the tank in spite of knowing that it's a very stupid thing to do!
In some cases it's all they can do. If you let the enemy tank get on top of your adc, the adc is gonna shoot the dude who is an immediate threat the said tank
If you're focusing a Tank as an Assassin or Mage then you should seek help...
ADC's should hit the closest target most of the time.
Some tanks are viable, garen/illaoi/darius those need to be focused
You act like it takes longer than 2 seconds to kill a tank.
This is a common thing that needs to be myth busted. The whole don't focus tanks thing isn't an absolute but just a caution in proper teamfights.
