Towers are supposed to be protected, not protect you.
So, I will probably get a lot of flame for this, but I gotta say it.
The objective of the game is killing the enemy Nexus, which is protected by towers. Therefore, killing the tower first is necessary and protecting them is important. So, towers are supposed to be protected. Sure, they offer safety with the damage they provide, but that's not their purpose.
Therefore, for all those people who say towers don't do damage and fall like paper, guess what. It's not their job to protect you sitting under tower, it's your job to protect them.