First officer is the time and place to learn by mistake.
Not at the expense of the passengers and cabin staff who can be badly frightened in any severe landing impact due pilot misjudgement. The time to learn is in the multi-million dollar full flight simulator under the tutelage of a competent simulator instructor who has the enthusiasm and flying ability to actually demonstrate what he wants - not just shout from the back.
Landing mistakes by the first officer - especially during line training - should not happen if he has had proper training in the simulator especially on crosswind landings. Pilots should not progress to line training until his approach and landings are consistently sound in the simulator. If that cost the company extra time and money, then that's a company problem.
Too many simulator sessions are a head-long rush to tick all the boxes. The result being rarely do we see first officers (and some incompetent captains, too) given sufficient simulator practice until these pilots are confident and confident in handling crosswinds, for example. I once observed a type rating candidate on an A320 simulator conducting an all-flaps up approach and landing on a 11,000 ft runway. He was far too high and fast over the fence - floated for 15 seconds or more and touched down well off the centreline with 3000 ft left to go. He over-ran the runway on to the grass.
Clearly he should have gone around earlier but he didn't. The simulator instructor looked at his watch and saw the session time was up. He ticked the box as all flaps up landing successfully completed, without insisting on further remedial training. The same first officer had similar problems with other parts of his type rating training and was simply out of his depth. But his boxes were ticked and that man has been let loose on line.