I Love Overwatch! It is a really good game but there’s some things wrong especially with rank. I’ve played so many games this season and every game I get paired with people who are clearly of a lower rank. Their positioning is wrong they make stupid mistakes and get 4K damage a game on bastion 
like come on! As a support main I can only do so much for my team and I don’t understand why the game just refuses to put me in plat. It’s actually starting to get on my nerves. 
On a positive note, as a support player and even with the nerfs I’m still happy and I think it’s more balanced than before although there’s still some work to do! Eg. BASTION is still overpowered even after his ‘nerfs’ and then he’s just dominating when he has a mercy glued to him!
So your issue is with the players performances and decision making.
Not ranked…?
Sadly, this happens in all ranks. No system is going to make people position better or use abilities more effectively.
If they did they’d be higher ranked anyways.
If you want to control your team mates, group up… There are plebs in silver there are plebs in diamond lol, it doesn’t stop, less plebs sure, but they are still there