Malicious contact after scoring

[DownTownTonyBrown]

Seems like we have had this discussion before but... one more time...

Reading situation 8.4.2 Situation Y
The bases are loaded with (a), less than two outs, or (b) two outs. B4 hits a ground ball to F4, who throws to F2 for the force out at home. The throw pulls F2 off home plate several steps toward the first base side. R1 seeing F2 ready to make a play on B4 at first base, touches home plate (SCORES) and maliciously crashes into F2. RULING: (a)Since this is a force-play situation, R1 and B4 are declared out and no one scores. R1 will be ejected from the game. In (b), R1 will be declared out and ejected for the contact, and no run will score.

Rule 3-3-1 n says A player who initiates malicious contact shall be ejected from the game.

Rule 8-4-2 e says the runner is out when he initiates malicious contact.

My question is, what allows me to negate an already scored run? Is there another rule I am missing or is it just this case play? Someone refresh my memory. Thanks