The squishy targets are right behind them, and your wasting moves/bullets onto a fat clunk of armor who deals like -10 damage. I'm already doing my job to tank the enemy's r%%%%%ed attacks who have no idea who to focus, and all you did was doing the same as well.
ADCs are supposed to attack whoever is closest while staying safe. If they can hit a squishy, they will, but don't expect them to get in melee range of their bruiser/tank who can probably CC them just to attack a squishy.
It is often difficult to get by heavy cc tanks/bruisers without being focused, cc'd, then killed yourself. Thus, you attack the weakest enemy you can attack safely. This is often a tank, especially if they are a good one.
Adc is a prime example of a person who is suppose to protect them self first. Most tanks have some form of cc so the ads must deal with that first. The assain or apc on the other hand should be able to get some damage on the enemy apc and adc. Tanks are there to be annoying and hard for the damage dealers to get around.
