People are quick at pulling out the rope here.
The Cirrus did not hit another aircraft, he was not even close. He didn't taxi as close as the presentation shows (otherwise he woul've bumped into the engine of the airliner) I'm almost thinking the fuselage of the cirrus couuld be on the outside og the wingtip of the airliner.
I have no clue about the sort of service being provided on that apron. If it's outside the manouvering area, it would normally be aircraft maintaining their own separation.... and well, he didn't bumb into the airliner....
If it's controlled, and the controller didn't know he was there.... different story.
If it's controlled, and the controller had given him a taxi clearance, but forgot about him.... different story.
If it's controlled, and the controller had given him a taxi clearance, but expected him to remain behind the airliner.... but not directly instructed it.... well, all controllers get a surprise from time to time.... those surprises go into your "bag of experience", and hopefullly become a part of the anecdotes used in training in the future.