Because the force was never removed.

The only relevant case play which makes NFHS and ASA different is 9.1.1-O In that play, B4 is out before R2 is appealed for missing the forced base and it is still treated as a force. In all of the other case plays, the BR is not out and therefore the result would be the same as in ASA.

In other words, ASA considers an appeal of a missed base to which a runner was forced to be a force out if the force is in effect at the time of the appeal. And NFHS considers an appeal of a missed base to which a runner was forced to be a force out if the force was in effect at the time of the miss.

The NFHS choice raises an interesting TWP. Runners on the corners with 1 out and R2 (a very poor base runner) stealing. BR hits it hard 5-3 and R2 aggressively turns at 2nd missing the base. F3 fires to second and a run down ensues. In the confusion R2 realize she can't make it back to second and instead scrambles toward first. After another unsuccessful rundown, R2 is now standing safely on first. The defensive coach then instructs his players to appeal that R2 missed second base. Does the run count? Does it matter if the coach knows that he's appealing the initial miss or the return?

I would say if I'm not sure what they are appealing, I have to ask. This one I probably would not have asked and just honored the appeal. I've had coaches yell 'I'm making an appeal'. Coach what are you appealing?

I've also had a runner touch the white base before the ball arrived. No physical contact so no interference. Called her safe and the girl stood on the base with the ball. runner returned to 1st. Coach calls time and comes out to appeal she touched the white base. OK coach but she returned before you appealed. My 1st baseman stayed on the base because she was appealing. Sorry coach, she gave me no indication she was making an appeal before the runner returned.