This is a very subjective take. Sure, if you’re playing a full rush comp or a very brawly style, then you want your team grouped up. That makes it more difficult (not at all impossible) for a smurf to isolate targets.
However, there are plenty of instances where this is just plain wrong. If you’re playing a dive style, or any comp with flank heroes, you don’t want to be grouped up so that your characters with less mobility can get in their own respective position.
Another example is if you have healers that aren’t brawling. You don’t want your Ana or Zen to be directly in the other teams face, grouped up with your tanks. You want them to be a safe distance away, prepared to heal. That’s the kind of target that’s easy for a smurf to ruin, whereas if a legitimate player at that rank tried to attack the backline it would be a much more fair fight.
You shouldn’t be bottlenecked into playing only one kind of comp and style of play just because there’s a smurf on the other team. Just because it’s possible to counter them doesn’t mean they’re not ruining the game by forcing you into a very specific style, where you’re still at a disadvantage anyway.