Welcome to ASC
Actually Brian M hit the nail on the head it is an issue of venue and nothing more. As a player you may not like to play with younger players, so you go to a different venue, no different that if you do not like the game style or type at a field.
Waivers must be signed by the guardian for anyone under 19, so no difference there. Although in BC with the various changes, the waivers changed a lot last year for all sports.
As for gear etc that is the Field owners responsibility to set and enforce, so any posts about eye protection etc are irrelevant.
Example our field allows any player from 14 up, all players must wear goggles with a full seal, anyone under 19 must wear field approved lower face protection. Don't like it leave.
We solved the drop off issue some fields have had with younger players, by requiring the parents to stay at the field for the 1st 4 days the younger players attend games. It also allows us to eject any problem kids right away, has not happened yet.
After that they are fine to leave, but must reachable, people do get hurt tripping falling etc.