I get what you’re saying. As a volunteer at Austin Animal Center, I walk 40-60 dogs a week, and in the past, have helped with dog playgroups. Running a playgroup where dogs get together and play requires training and skills. Dog body language and temperaments are hugely important and only those with experience or training can manage issues that arise safely. Safely is the keyword.
Another thing to note is that if anyone boards their dog(s) at a facility that runs playgroups, all dogs are required to be evaluated first before they can even board. There is a reason for this. The dogs are usually evaluated by experienced and skilled people who understand dog body language and temperaments. Dogs are like people in that they don’t have to like every creature of the same species that they meet. A dog-friendly dog to many dogs can all of a sudden really dislike a new dog they just met for a variety of reasons (play style, body language only dogs can read, etc)
I say all this to show that getting many dogs together to play sounds fun (it truly does- I enjoy watching playgroups at the shelter), but most humans that bring their dogs to these parks are not trained to see when another dog is stressed or uncomfortable, and also not trained to properly break up a dog fight.
I might be sounding too serious or making too big of a deal about this, but it’s all fun and games until a dog fight erupts and a human gets bitten from improperly trying to break it up. It won’t be an “if it happens” situation, it will be a “when”. I cannot support a situation where the safety of animals and humans is at risk. A good read: https://www.nytimes.com/2020/02/06/smarter-living/the-dog-park-is-bad-actually.html . Thank you for hearing me out. Dogs are my life.