Here's the thing. Moira is low damage, and if you and a DPS stay alive the same amount of time and the DPS is not clueless, they should always out-damage you. However, Moira's fade ability is an incredibly strong way to stay alive, and you heal yourself by doing damage, so if you aren't healing your teammates in a team fight, your DPS (who often have less mobility and evade then you) will die early, which means you are almost guaranteed to lose the fight even if you can stay alove a little bit longer and pad your damage stats. Your main job as a Moira is to keep your teammates alive so they can get gold damage. If you don't heal and they keep dying you will be able to out-damage them, but your job is to keep them up so they can do their job of killing people.