And the marshals made the situation worse by seemingly being clueless as to how the debris clearing had to be done safely, i'm sure just running out and randomly kicking car parts about without wearing any safety gear isn't in the training.
No marshal should ever be sent onto on the track like that unless the cars are lined up behind the safety car (and have finished whatever pitstops they have to do) the race can wait if it keeps the marshals safe.
I bow down to your obviously greater knowledge as to how to remove debris. I assume you have been to many marshals training days as you seem so confident as to how things should be done. If that is true then I assume you were the one at the back half asleep (there is always one in any training seminar) during the section about handling debris.
In most cases kicking debris off the racing line is the recommended way to deal with it. It is a bloody sight quicker (and hence safer) than having to bend over and pick the bits up, but the main reason for kicking the bits is that you have no idea how hot those bits might be until you pick them up and they start to burn through your gloves, by which time it is too late and rather than helping the situation you now become part of the problem.
Removing the debris, especially carbon fibre bits, is best done whilst those bits are relatively big, waiting till they have been run over and broken in multiple small pieces tends to prolong the length of the clean up process and I'm pretty sure that most marshals would agree that the shorter the time you are out there the better.
As for your last paragraph, adhering to that rule would result in an indefinite SC period, given that any car in the train can enter the pits, and hence be in catch-up mode at any time. Not sure how that would go down with most viewers - many posters on here tend to get somewhat annoyed every time the SC car comes out.
I will now retire from the discussion as I do not have a suitable tin-hat for protection from the flak that I assume will be fired my way.