Are these rules the same for baseball? If not, you may want to bring that to their attention. It may be a tougher sale with baseball parents and you can object to the discrimination.
My local baseball is Pony, compared to LL they have less mandated safety rules. For example, composite bats are still allowed. I know that a growing number of the Pony pitchers are wearing heart guards out of choice, not because it is mandated by the league. I made my own DD start wearing a face mask when pitching as a first year 12U player when several pitches came straight back at her and narrowly missed her head. She continues to wear it today as a 16U when she pitches and also when she plays 3rd. She tells me it gives her the confidence to play at the edge of her abilities without worrying about her face.
As for your suggestion on discrimination. That is a logical argument that takes the cognitive ability to separate emotions from the decision making process. The group of parents pushing these rule changes live on the emotional impact of their decisions. The what ifs in life. Trying to get them to follow a logical argument is not worth my time.