Off the lead

This may seem like a stupid question but why do people let their dogs off the lead in public places ?

I can understand the want to let the dog “run free” but there are private gardens or dog parks for that.
Anywhere else, with the responsibility in case anything happens, and especially with so many uneducated owners/dogs, why do people continue to let their dogs off leads ?

There are too many cases of strange dogs coming up to people (with or without dogs).
I, for one, go on organised hikes every week (often solo) and despite having my girls, I am not comfortable with dogs off leads coming over to me, however friendly the owner might claim them to be.

On the other hand, how many times people ask me why my girls are kept on a lead.
Despite being afraid of losing them or not being in total control, they can run free at home in my garden. In strange places, I won’t take the risk of them getting hurt. In any case, a 5m lead is great for giving them enough freedom whilst keeping them from causing any trouble.

Thoughts ?

I think there's a halfway house between always and never.

Mine are off lead most of the time but if I see another dog or even just a person I put them on while we pass. Even though they have the garden and fields here, they do enjoy snuffling on walks off lead and as long as they're under control when we meet anyone then I don't have a problem with that.

Nola and Chaos are also on lead in the forest in France a lot as it's full of deer and boar, which are all a bit too tempting. I don't like dogs chasing wildlife.

I've nothing against off lead dogs (except along the public roads) as long as they're under control & have a good recall.

What I absolutely hate is an off lead dog that goes up to every dog/person around, without permission & usually accompanied by "It's okay, mine's friendly!" 

My boy is off the Lead too 90% of the time I put in a lot of work to make him the dog he is today he stops at roads, Entrances ect all I have to do is say wait he's almost a little human lol, long as your dog is under control and doesn't jump up at every person they see or Poo in public and you don't pick it up I live in a small town in the country and people are very quick to judge but iv changed a lot of peoples opinions against Staffys .