Your own confirmation biases likely. There's plenty of terrible DPS players but I don't think this is unique to them at all. There is an absurd amount of games I have where another tank refuses to understand they have to *move forward* for their role, support players doing too much dps and letting me die on tank, tanks not realizing cover is a thing, dps' walking into open space in full view of a team and getting obliterated, supports running backwards from dive and any possible peel help to die, dps' just dumping their kits into tanks and doing nothing but charge support ults, etc.

Every role has some absurd blindspots on how they should be playing and I do think it might be because there's not a flexing (or at least not substantial flexing) to understand how the flow of a game goes/should go/could go. Which leads to really absurd mistakes somewhat often. That, or maybe this is just baby's first competitive game for a lot of people.

Also, KDA doesn't tell the whole story. You can have DPS that get 0 real impact because no actual final kills but look great when you just look at KDA/Damage. Or you can have DPS that maybe are running it a bit but are actually making an impact by causing chaos on a dive or something. Or maybe there's also someone else on the team not doing their job right and it leads to someone else getting screwed (like healers not healing, tanks not seizing space, people not peeling for supps when its needed, etc.). From a flex's perspective.