This just shows that you are clueless about teamfighting, and have not even attempted it ever.
Ideally, you are supposed to engage the enemy simultaneously with your teammate, as you go in-line with him, so that is the goal here.
In practice however, most players are dimwitted and do not understand this, and will not even be aware of presence of teammates around them. They absolutely cannot be counted on to support me in my atack. Again, you would completely know this if you had tried it even once.
So, I absolutely cannot trust them to strap in when I atack. But, I can trust myself to support the other player when he atacks, and thats what I do. I stand a little behind the guy, just enough to have him in my view and see what he is doing, to atack when he atacks. An almost-simultaneous atack can be achieved like this. It has nothing to do with "hiding behind teammate". It works, and you know it very well. I have personally been killing you like this. I am shure you would prefer for people to come in one by one to kill them with your cheat, and when my teammates werent awful, I had been successfull in denying you this. Remember that 1 life match when your side lost like 4 matches out of 5?
When the teammate is bad, he may go too fast and aggresively, and I will be left too far behind him, that I will not be able to move in fast enough to support him. In that case, the most I can do is to be the second atacker and clean up the mess after he dies, or retreat. Obviously, when this happens, I have no time to fall out and get in-line - when teammate runs forward, and I am following teammate, I will be behind the teammate. No ♥♥♥♥. So, a clueless observer like you would interperet it as if I am hiding behind teammate. Mega brain.
When playing, I do not just run around randomly. I will look for my teammates and go toward them to support them. As I go toward them, I will be, like, behind them. So thats how your primitive mind works - to your eye, I am obscured by teammate, so you think "oh he is hiding behind the teammate". Undersand that an ordinary toilet-player would just ignore the team and would abandon the fighting guy, and I am trying to be there to help them out. How dare you to think of that with contemt? Also, obviously, I would avoid fighting more than one enemy or a cheater alone. I would run back to regroup with my team and fight them when we have more force. I cant believe I even have to say this. Am I talking to a dimwit? Fight when you are stronger, dont fight when enemy is stronger.
Why talk about things you dont understand? Mouse-jerkery is 100% of all game knowledge you have. Have some respect for your betters.