Aikidoka have simply been taught wrong.
The guy in the first video is amazing, but let's talk practical application...(he was planting his feet first every time)...from a bicycle or a shove: his rolls looked like Aikido rolls; to me at least.
The second video with the two guys was awesome but nothing new under the sun. I certainly wouldn't "plant" my hand; just more factors for injury.
I liked the russian guy's rolls but I wouldn't recommend that from a height at the risk of breaking my neck. Literally.
Great post thanks.
One more thing and correct me if I'm wrong but an Aikidoka's roll allows him/her to maintain a weapon in hand whereas the others we saw here excluded that possibility.