Understanding an interference rule

[CecilOne]

This is just for understanding, although if not understood, maybe concern on how to call a play and how to teach.
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Play: (Fast Pitch) With less than two outs and 1B is unoccupied. B2 swings and misses strike three. F2 misses the ball and it bounds off the catcher and under the feet of B2 on their way to 1B. B2 unintentionally kicks the ball when out of the batter's box. What is the call?

Ruling: If the umpire judged that the kicking of the ball by B2 impeded, hindered or confused F2 or F3 making a play we have interference with a dropped third strike. The ball is dead and B2 is out. Rule 8, Section 2, Article F [6].
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I understand that the rule item 6 says “with a dropped strike”, but I don’t get why that is different than items 3 and 4.

The Ruling says interference if the contact with the ball “impeded, hindered or confused F2 or F3”; which implies that the BR has to interfere with a fielder, not just the ball, similar to item 2.
Why do items 3 and 6 only say “ball” when they mean “ball and fielder”?

Is “unintentionally” in the play just to force thinking, or because it was copied from an old play; or does this particular case treat intent differently?