I got thrown like that by my Japanese sensei. We had a padded wall at the university dojo, and it wasn't uncommon to get slammed into it. Part of the purpose is so that you learn awareness of where you are, and how to maneuver out of the situation. I was taught to never turn my back (unless throwing) in randori or shiai (when going back to the line, even if matt'e called), and I got only one verbal warning. Same thing for getting up off of your knees. I got to the point where I was always trying to break free of the grip as I was going down, turn to pull guard (not called that back then), or jump up and make an attack as I was getting up.
That's stuff that is probably pretty common in Japan, in university dojo at least, but I've never been so I can't say for sure.
It's an other world, one in which few people will (or would want to) be involved in.
My coach never smashed me against a wall, he certainly threw me hard, I got straight back up and charged him only got get smashed over with Tai otoshi/Uchi mata. I remember one incident where I got smacked, bounced back up, he had his back turned jto me, doing the old circle undo belt and then rejoin, and I grabbed him, turned him round only to get immediately walloped over with Tai otoshi for my troubles.
I've actually been strangled more times on all fours than thrown, usually knocked down by a Sasae or Ko uchi only to get my gi whipped across my neck and a strangle, accompanied by a smirk, applied.
I think Jap universities are another world, my coach was beating a Jap at Tokai and Yamashita himself called this Jap over, beat him with a stick whilst giving him a bollocking and then sent him back out to the mat. My coach let the guy get a few throws in whilst Yamashita was watching, just because he felt sorry for the guy.
And we think of Yamashita as this nice, kind, affable, gentle giant. Imagine what the likes of a Yoshida or Shinohara would do...
Like you say, not a world I could survive in and not one I would like to be in. Wouldn't mind the skill, just if I could skip the hardship... lol.