You seem to have ignored that this section appears to be on a public road (as quite a few rally events are..)
The drivers KNEW THE POLE WAS THERE. SOME of them tried to push it too hard, and they took the consequences. Also, just because the video shows all of those cars hitting the pole doesnt mean they all hit it.. Although I cant seem to find any more details about what/where this event was.
If you only watch crash compilations, you'd end up making a guess that almost every single rally racer crashes during the same race.
At some events, especially particular stages, sometimes that can be quite close to being entirely accurate. And most rally events have a host of amazing drivers and a large number of "amateurs" (could be Pro, just not as good as the top of the crop). Many crash compilations (if it is only showing one turn) end up really only showing the lesser-known people.
And I also have a feeling that was a more "amateur" race. I don't know all that much about how it is done in Europe with the WRC, but in the U.S. there is the National Championship series (a handful of events each year, all the big names try to attend and earn the points for the series), and then a large number of Regional Events, which regional leadership boards (the big names don't attend these, not often at least).
I didn't recognize a single car in that video, though like I said I don't keep serious track of WRC, though I do follow RallyCar (RallyAmerica).
But even the big names crash, and they do that often... sometimes one or two turns in a specific stage can send half the pack careening off the road toward danger or massive damage.
And hell, in Rally, most often at least half the track is a danger zone.
Steep ditches or dikes, nasty drop-offs if not straight cliffs, boulders or other random obstacles around the road.
And every single driver gets to go through the course at legal speed iirc (speed wise I am not 100% sure, but they get to drive it) and make quick notes about turns, appropriate speeds, best side of the road to be on at a certain point, etc. They all are well-aware of every single danger.
Is it possible for 10+ drivers to make the same mistake, and still call it a mistake? Yes, because they knew the situation, and they should have known what they would need to do to not make a mistake (that's on the driver and co-driver to accurately judge the turn the first go around, and then make the correct judgment when faced at speed).
Rally can be super dangerous, and no team will ever make it long on a single car (or at least go for long without extensive repair).
Easily the hardest type of racing out there, even if it's not nearly as fast, on dedicated courses, and coupled with race stands.
Hell, quite often the average speed for a stage is right around 60... favorite type of race.