It might be self inflicted wound but when the players are forced to walk through tight hallway filled with spikes it's hard to avoid wounding oneself.
Look at the Ex primals - casual content closest to the raiding. I still have the pain in my recent memory, you make a group to train part 7 of the dance and it's great success if you can even get to the part 4. Telling players to find a static group is the safe route, because most of the better players are in the static groups and these good players are also unlikely to do content with other players much. Statics provide you certain level of insurance that players are going to be responsible for their gameplay and of course they are showing better performance and attitude when they are afraid of being removed from the groups. On the other hand random groups, be it PF/DF or RF, are bound to have many yolo players who either think they are better than they really are or who want to be carried by the rest of the group - which simply does not work in content like savage. One person trying to cheat their way is enough to persuade the other 7 players to just give up so finding a static can save you a lot of frustration. And we haven't even got to the point that there are many possible strategies for clearing content which have to be trained for their correct execution.
And we can't entirely say that the wound is self inflicted only by the players themselves. Things like the casual content being such faceroll are helping plenty to create the community issues.