Both?
We all know there's toxic players out there, who troll and cause trouble and generally act like jerks. We see them around here too. Every game has them, although there's fewer here than in a lot of other games.
We also know there's people who want to be carried and really hate to be called out on it, claiming that it's toxic to point out that they're not even trying. Then we have this trend I've been seeing more lately of DPS players queing as healers and then never healing just to get a faster queue. That crap needs to be stomped out mercilessly.
Bad players are out there. Some of them are quite content being bad, and some of them want to get better. You can tell which is which by how they react to advice.