Been noticing this more and more recently myself. But to me, dummies with no aim picking Ana is more of a cancer on this game. I always have an Ana on my random teams, and never get healed. Some of them will not even bother healing you unless you stand still.
I know the feeling. I've played with some of the most useless Ana's as well, ones who just use her as an offensive character instead of a healer. I refuse to use her offensively unless my entire team is healed or I am by myself and someone is attacking me. Otherwise, I'm sniping my teammates in the head. I get that she can take out people easily ever since they gave her a buff to shoot faster, but if I'm dying or someone else is and you're too busy sniping the enemy instead, you're useless.
But my favorite thing with Ana is when I pick her for attack, and someone else feels the need to choose another sniper. And don't you dare bicker about it, because they will say, "Well, you're playing as a sniper too." These are the people who have absolutely no clue what they're doing in this game, care about medals, and complains that no one is attacking the turrets while they're playing a character that can easily snipe them away...