Overwatch is a game of tactics. You can't accurately represent teamplay by reducing it down to a couple numbers.
The problem with damage medal is it that damage doesn't mean anything unless you get a kill. Certain heroes just inherently do more damage. Junkrat is going to splash damage around everywhere. But if the enemy runs away and heals, then all you've done is fed the enemy support ult charge.
The problem with elim medals is it that it doesn't say who those targets where.
Example: A widowmaker that can consistently get one kill before the rest of the team engages, turning a 6v6 into a 6v5, is very useful.
A widowmaker that comes in at the end of a fight, when it's 6v2, and you've already won, and the remaining two are running away, and she kills them, is significantly less useful. But she has twice as many kills.
Also remember than an elim only requires that you do one point of damage to a target that is later finished.
Medals can be an indicator, they're not 100% useless.
But they're not 100% infallible either.
When it becomes a real problem is when someone is holding their team back, refusing to switch, because they genuinely believe they're doing great (even though the entire rest of the team sees otherwise) just because they have a damage medal.
And saying "if you don't have gold damage as soldier then you're bad" isn't helping anyone because we don't know the whole story of what's going on.
Maybe the soldier was really good, but the other dps on the team were just that much better.
Maybe there was a high splash damage character going around splashing everywhere.
Maybe the enemy team kept feeding a Zarya to max energy and Zarya wrecked them. I've had that happen.
There's simply too many possibilities to dumb it down to "if you don't have gold, then you're bad"